당신은 주제를 찾고 있습니까 “ground vibration sensor – Ground vibration sensor string“? 다음 카테고리의 웹사이트 https://chewathai27.com/you 에서 귀하의 모든 질문에 답변해 드립니다: Chewathai27.com/you/blog. 바로 아래에서 답을 찾을 수 있습니다. 작성자 Technology for Wildlife 이(가) 작성한 기사에는 조회수 51회 및 좋아요 없음 개의 좋아요가 있습니다.
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Indegenious sensor string in series and parallel configuration. Separation between two sensor is 1.5m.
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Ground Vibration Sensors | Products & Suppliers – GlobalSpec
Application of accurate ground vibration sensors combined with analytical and numerical methods in solving ground wave propagation can robustly and accurately …
Source: www.globalspec.com
Date Published: 3/14/2022
View: 4138
Sensors and Shakers for Ground Vibration Testing
GVT (Ground Vibration Testing) uses TEDS ICP® accelerometers, cables, patch panels, and signal conditioners for modal analysis response measurements. Shakers …
Source: www.pcb.com
Date Published: 5/22/2021
View: 1697
Ground Vibration Sensor – BEI Security
Ground Vibration Sensor. Perimeter Security, Veo Intrusion Detection, Fiber Optic Security System, Marine Security, Marine Net, Under Water Marine Net …
Source: www.beisecurity.com
Date Published: 11/6/2022
View: 2075
주제와 관련된 이미지 ground vibration sensor
주제와 관련된 더 많은 사진을 참조하십시오 Ground vibration sensor string. 댓글에서 더 많은 관련 이미지를 보거나 필요한 경우 더 많은 관련 기사를 볼 수 있습니다.
주제에 대한 기사 평가 ground vibration sensor
- Author: Technology for Wildlife
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- Date Published: 2020. 12. 26.
- Video Url link: https://www.youtube.com/watch?v=RhboOg_K-KE
How do you monitor ground vibration?
Ground vibration monitors use a transducer, also called a geophone, to measure vibrations. To properly measure these vibrations, securely couple the geophone to either the ground or a structure. This ensures that the geophones sense all the energy in the ground.
What causes ground to vibrate?
Ground vibrations can originate from a number of common sources, some of which are – rail and vehicular traffic, jackhammering, bulldozing, pavement milling, vibratory compaction, pile driving, and blasting.
What type of sensor responds to vibrations through the ground?
Accelerometer. By far the most popular vibration sensor type is an accelerometer.
How does vibration sensor work?
Vibration sensor detects the vibration parameter of objects through its mechanical structure, and converting the vibration parameter into the electrical signal by physical effect to achieve transferring the non-electrical signal to electrical signal. …
Is there an app to measure vibration?
The mobile app gives users a high-performance, lightweight alternative to more costly systems. The VibroChecker app from Ace Controls uses the acceleration sensors, gyroscopes and microphones integrated in the iPhone and iPad to measure vibrations on machines and components within a frequency range of up to 50 Hz.
How do you measure vibration in a house?
Vibration occurring in a structure can be detected directly using an accelerometer, a displacement transducer or a velocity transducer. The Peak Particle Velocity is the maximum absolute value of the unweighted signal (particle velocity signal) over the duration of the measurement.
How do you stop ground vibrations?
Test results have found that increasing joist depth and sheathing thickness can greatly reduce floor vibrations. A final element to help prevent vibrations is making sure floor sheathing is glued and screws are used over nails to control long-term bounce.
What frequency does the ground vibrate at?
The Earth behaves like a gigantic electric circuit. Its electromagnetic field surrounds and protects all living things with a natural frequency pulsation of 7.83 hertz on average — the so-called “Schumann resonance,” named after physicist Dr.
Can vibration causing structural damage?
Vibration Analysis. Construction vibrations are a known nuisance and can damage existing structures if they are not properly monitored and accounted for. As a proactive means to mitigate vibration damage claims, nearby buildings should be inspected prior to and after construction and monitored during construction.
What are the different types of vibration sensors?
The general types of vibration sensors include displacement sensors, velocity sensors, and accelerometers. Accelerometers are the best choice for most industrial rotating assets because they are simple, easy to apply, and very sensitive to the high-frequency vibrations typically generated during force-failure.
Which sensor is used to sense vibrations?
Accelerometers
By far the most common types of vibration sensors, accelerometers measure the changes of velocity of a given component. When attached to a piece of equipment, any vibration will reflect a change in velocity, which will cause the accelerometer to produce an electrical signal.
What is vibration shock sensor?
The Wireless Piezo Shock Sensor is advanced warning device designed to protect window and door surroundings against forced entry. The sensors detect shock waves, which is alerted to vibrations through the piezo sensor.
How do you test a vibration sensor?
The output of the sensor is read using a multimeter. First, readings should be taken with no vibration. The vibration level should then be increased at a given frequency until vibration levels reach the top of the measurement range for the sensor under test.
What is the output of vibration sensor?
Vibration sensors (4-20mA)
They provide a 4-20 mA output signal proportional to the overall vibration level. The 4-20 mA output is commonly accepted by process control systems such as a PLC, DCS or SCADA system for cost-effective continuous vibration monitoring.
How is construction vibration measured?
Vibration occurring in a structure can be detected directly using an accelerometer, a displacement transducer, or a velocity transducer. The measure is a Peak Particle Velocity which is the maximum absolute value of the unweighted signal (particle velocity signal) throughout the measurement.
How do geophones work?
A geophone works using a coil of wire wrapped around a mass, suspended by a spring over a magnet. As the mass moves, the magnet moves the electrons through the wire coil producing an electrical signal (voltage). Seismographs record this voltage signal.
What is peak particle velocity?
Measurement of the environmental impact of ground vibration from blasting operations is based almost exclusively on the peak vibration level generated. This measurement is known as the Peak Particle Velocity or PPV.
Ground Vibration Monitoring
Ground Vibration Monitoring Mission Statement:
The Ground Vibration Monitoring website seeks to answer the most common questions pertaining to ground vibration monitoring in order to help the user determine…
What is ground vibration monitoring?
Who uses ground vibration monitoring?
How do ground vibration monitors work?
Where can I rent ground vibration monitors?
In addition, it provides information pertaining to recommended instruments, basic monitor setup, industry standards, and a page of posts containing frequently ask questions and troubleshooting.
What is ground vibration monitoring?
Ground vibration monitoring is the process of measuring and recording the movements in the ground using a seismograph. As vibration occurs at a source, a seismic wave travels causing soil and rock particles to move back and forth over very small distances. This is known as particle velocity. The vibration monitor measures the Peak Particle Velocity: the maximum speed of a particular particle as it oscillates about a point of equilibrium, caused by the traveling seismic wave. By measuring the Peak Particle Velocity in inches per second, operators indicate whether damage is likely to occur to surrounding structures.
Unlike large, permanently-mounted seismographs that measure earthquakes or other geologic events, ground vibration monitors are small and portable with the ability for programming specific parameters. Therefore, an operator programs the unit to specific parameters that only record during a given time period or only trigger a recording once a certain criterion occurs.
Generally, these monitors record man-made vibrations as opposed to natural seismic occurrences. To learn more about monitoring natural seismic activity, please visit the U.S. Geological Society Earthquake Monitoring page.
Who uses ground vibration monitoring?
Ground vibration monitoring records vibrations caused by traffic and construction projects as well as quarry and mining operations. Engineers and construction companies usually assess their ground vibration to make certain that machinery and construction work does not cross a threshold, causing structural damage to neighboring buildings and infrastructure. Likewise, quarry and mine operators monitor the vibration caused by blasts, compaction methods, and heavy machinery/equipment. In some instances, they use the monitors to measure the damaging air overpressure caused by a blast and fine tune their blasting techniques.
All ground vibration is of some concern. Most heavy construction projects centered in urban areas and industries involved in blasting require monitoring the ground vibration that they cause. However, that doesn’t mean that homeowners or businesses near these sites should not contract an experienced company to perform ground vibration monitoring. The ability to prove that ground vibration from an outside source caused or did not cause damage protects those that pay to conduct a survey. Ultimately, the reports from vibration monitors prove helpful in demonstrating whether vibration is great enough to cause concern or not.
How do ground vibration monitors work?
Ground vibration monitors use a transducer, also called a geophone, to measure vibrations. To properly measure these vibrations, securely couple the geophone to either the ground or a structure. This ensures that the geophones sense all the energy in the ground. Inside the geophone, a spring-mounted, magnetic mass moves within a wire coil when the ground vibrates. This produces an electrical signal proportional to the ground vibration velocity that the monitor records.
Ground vibration monitoring measures three types of ground vibrations.
The ground vibration monitor’s transducer is a triaxial geophone. This means it measures vibration on three planes. Transverse ground vibrations cause particles to move in a side to side motion. Vertical ground vibrations cause particles to move in an up and down motion. Longitudinal ground vibrations cause particles to move in a back and forth motion progressing outward from the source.
To receive good results and properly distinguish transverse vs vertical vs longitudinal vibrations, orientate the geophone correctly. The arrow on the geophone must be visible; otherwise, the geophone is upside-down. Point the arrow on the top of the geophone towards the seismic source. Make certain the geophone is as level as possible. Finally, fasten the geophone securely to the ground or structure. Most geophones come with spikes that stick into the ground. If the ground or surface does not permit spikes, the unscrew the spikes and the couple the geophone to the surface by placing a heavy sandbag over it.
Do ground vibration monitors measure anything else?
Because monitors often record blasts in the quarry and mining industries, microphones are sometimes used to measure air pressure. This damaging air pressure is commonly referred to as an “air blast”. By measuring air pressures, these industries determine the effects of the air blast energy on structures. The monitors connect to two different types of microphones: Linear “L” microphones or “A” weighted microphones. Predominantly, operators use Linear “L” microphones to measure the effect of low frequency air pressure on buildings whereas “A” weighted microphones measure noise levels people consider an annoyance because it’s a scale similar to the human ear.
Where can I rent ground vibration monitors?
Several environmental equipment or geophysical instrument companies rent ground vibration monitors. The Ground Vibration Monitoring website recommends K.D. Jones Instruments.
K. D. Jones Instruments rents Instantel Minimate Plus and Blastmate III units for reasonable rates. These ground vibration monitoring units arrive fully charged as well as factory calibrated. Generally, factory calibration occurs once a year for each unit. Moreover, K.D. Jones Instruments checks every unit for functionality before sending an item to a customer. All in all, over 25 units are available and ready to rent. Typically, vibration monitors are sent with geophones with a 2 to 250 Hz range. Moreover, they conform to use with the ISEE (International Society Of Explosive Engineers) standard.
In addition to the vibration monitor, accessories such as DIN geophones, waterproof geophones, extension leads, alarm boxes, field printers, uninterruptible power supplies, or linear microphones are available upon special request.
Find help with Minimate Plus and Blastmate III setup at VibrationMonitoringCourse.com.
Ground Vibration Damage on the Rise – Origin and Cause: Forensic Engineering Canada
Ground vibrations can originate from a number of common sources, some of which are – rail and vehicular traffic, jackhammering, bulldozing, pavement milling, vibratory compaction, pile driving, and blasting. The magnitude of these vibrations can range from being entirely unnoticeable, to a minor nuisance, to extremely damaging. Generally speaking, factors that dictate the effect that ground vibrations may have are the strength of the source vibrations, duration of exposure, distance from the source, type and condition of the affected building, and the local soil type. But here is the reality of the matter: Urban development is on the rise and frequently with construction often taking place alongside aging building stock and infrastructure. Consequently, there will probably be an increase in vibration damage claims and here is what you will need to know.
Direct Damage
To best explain this aspect of structural engineering it is necessary to get technical. Ground vibrations are typically quantified in terms of Peak Particle Velocity (PPV), which can be expressed in millimetres per second (mm/s). Stronger vibrations have a higher PPV. While in Canada there is no national standard for ground vibrations, in other countries it is generally agreed that ground vibrations should not exceed 5 mm/s.
This 5 mm/s threshold is intended to minimize the risk of cosmetic cracking in drywall, plaster, and old unreinforced masonry. If the building is well constructed and in good condition, or if exposure to the vibration is very brief, it is possible for a building to tolerate even stronger vibrations. On the flipside, while instances of this are rare, it is also possible for damage to occur at levels lower than 5 mm/s. But this threshold applies to direct damage only; vibrations can also cause damage indirectly, as a result of soil movements caused by the vibrations.
Indirect Damage
Vulnerability to indirect damage depends on the local soil and the duration of exposure. Soils such as sand, gravel, and some fine-grained soils known as loess, can be compacted and compressed by vibrations, which in turn can result in foundation movement and cracking. Imagine the particles in loosely compacted sand like a house of cards: The vibration makes the particles move around and fall into a more compact configuration, like when a house of cards collapses. Unlike direct damage, there are no standards limiting vibrations to prevent soil consolidation because more research into the problem is needed. However, damage to buildings has occurred in some susceptible soils at vibration levels below 1 mm/s. Therefore, when investigating a vibration damage claim, both the soil characteristics and the ground vibrations need to be considered.
The Human Factor
Building occupants are usually much more sensitive to vibrations than the structures themselves. Vibrations of just 0.3 mm/s can be enough to disturb some homeowners, and vibrations of about 1 mm/s are likely to result in complaints. A vibratory roller compactor working in an area with very hard soils might cause complaints more than 400 feet away! This is why the sensitivity of the occupants is frequently an issue with vibration damage claims. Often, when building owners notice these vibrations, they go looking for damage afterwards. They may find a number of cracks they had never noticed before, which in many cases were actually pre-existing.
Documentation and Communication
Cracking caused by ground vibrations may be indistinguishable from other types of damage. Therefore, a vibration damage investigation involves a lot more than a visual examination. Additional information needs to be considered, including the local soil conditions, the type of building involved, general condition of the building, and the duration, frequency, and source location of the vibrations. But the most valuable information can be documentation of pre-existing conditions. Unfortunately, that information is rarely available.
If you look hard enough, you will find cracks in any house. As a homeowner, it is a good idea to go looking for those pre-existing cracks and take photographs as soon as you see any construction work going on nearby. That way, if damage does occur, you will have some documentation of existing conditions from when the construction work started. That record of pre-existing conditions will help in determining the extent of the damages.
If you are a contractor, the best way to prevent complaints is to inform residents if they should expect ground vibrations, and to conduct pre-construction surveys to document existing cracks. Nuisance vibrations are more tolerable when they are expected, and if you perform a pre-construction survey, owners will not be discovering pre-existing cracks while the construction work is going on. If vibration damage does occur, a record of pre-existing conditions will help limit the costs of the claim.
Contact A Structural Engineering Expert
Whether caused by jackhammering sidewalks, new road construction, pile driving, or rock blasting, ground vibrations are a complex matter. They could be nothing more than a nuisance, cause superficial damage to your home, or they could even cause serious foundation damage. Our forensic structural engineers have the necessary experience and expertise to help you with your next vibration damage claim.
Vibration Sensor Types and Where to Buy Them
Vibration measurement isn’t always a straightforward task. Not only are there many different instrumentation and software options you must choose from, finding vetted suppliers can be a task in of itself.
In this post, I’ll list and explain the common sensor types and systems used to measure vibration. When I can, I’ll also provide links to suppliers online where you can purchase these sensors (although some companies still require you to request a quote – stupid I know). For each sensor type, we’ll start off with a list of suppliers and the pros and cons before diving into more detail.
I know you’re short on time, so I’ve started the post with a summary table of the sensor options I’ll cover. At the end of the post will be additional resources if you need further help in your vibration testing!
Sensor Type When to Use When not to Use Top Supplier Accelerometer General purpose shock and vibration Limited budget and access to necessary electronics PCB Piezotronics Strain Gauge Curved surfaces, when size and mass are important, need strain data Time or wiring constraints, need to measure acceleration HBM Velocity Sensor High temperature (> 700 °F) applications Hard to find, generally better to use accelerometer and integrate Gyroscope Orientation data is required Typically not used on their own, but with accelerometer Analog Devices Microphone or Pressure Health monitoring, determine vibration frequency To measure acceleration directly, determine vibration at known locations PCB Piezotronics Laser Displacement Measure displacement directly without altering your structure or product Outside of the lab, when power is a concern KEYENCE Eddy Current or Capacitive Displacement Measure displacement directly without altering your structure or product Outside of the lab, when power is a concern Lion Precision Vibration Meter Quick go/no-go diagnosis of machinery Transient events and longer than 15-second tests Fluke Vibration Data Logger Save time & cost, testing in the field (portability important) Modal testing, very fast sampling needed (> 20 kHz) enDAQ (a division of Mide Technology)
Contact Vibration Sensors
The following sensors require mounting the transducer to the vibrating test piece. This has the advantage of moving with the test article to measure absolute motion, but this requires a slight modification to the vibration environment (adding mass can change the mode shapes and frequencies). Also, pay special attention to mounting the sensor. In order to accurately measure the motion, a good coupling must be achieved between the sensor and the test article – mounting matters a lot!
Accelerometer
Accelerometer Suppliers Accelerometer Pros Accelerometer Cons PCB Piezotronics
Endevco Meggitt Sensing Systems
TE Connectivity
Analog Devices
Bosch Sensortec Very popular = lots of options
Variant exists for virtually every application
Accurate with low noise Need to integrate for velocity and displacement
Requires supporting electronics
Mounts directly on vibrating test article
Accelerometers are the most common sensor type for vibration testing. [Image Source]
By far the most popular vibration sensor type is an accelerometer. As the name implies, accelerometers measure acceleration levels which are generally reported with the symbol g (equal to the acceleration of gravity, 9.81 m/s2 or 32.2 ft/s2). For some applications you may be more interested in the velocity or displacement than in absolute acceleration levels, but this can be calculated by integrating the acceleration data. For periodic motion, this integration can be very accurate but for transient events like shocks, this can lead to run-away integration error. Therefore it’s best to do integrations for small time segments where the vibration is very periodic to calculate the velocity and displacement data.
There are three main types of accelerometers: piezoelectric, piezoresistive, and capacitive MEMS. The working principle of these are all slightly different and therefore the best applications for each accelerometer type is different.
Piezoelectric Accelerometer
Piezoelectric accelerometers are the most popular for their wide availability and high signal-to-noise ratio. They are AC coupled though so they can’t measure static accelerations like gravity. They can also experience issues when excited at their internal resonance. They are typically between $300 and $3,000 per axis.
Piezoresistive Accelerometer
Piezoresistive accelerometers are becoming increasingly popular because they overcome the issues a piezoelectric accelerometer experiences at high (internal damping and don’t magnify resonance issues) and low frequencies (measure down to 0 Hz). But they are typically 2 to 5 times more expensive than piezoelectric accelerometers.
Capacitive MEMS
These are the type you’ll find in your phone. Capacitive MEMS accelerometers are the most cost-effective accelerometers (down to <$10 price range) and are typically PCB board mounted. Their data quality is typically much noisier than piezoelectric accelerometers and limited to bandwidths below a few hundred Hertz. But the quality is improving and for many general purpose applications, the data quality is plenty good enough. Strain Gauges Strain Gauge Suppliers Strain Gauge Pros Strain Gauge Cons HBM Don't look elsewhere -just buy online from HBM OMEGA Vishay-Precision Many different options & inexpensive Can be used on curved surfaces Very accurate Wide frequency range Installation is... not easy Requires special electronics Measures strain in a material - not acceleration How does a strain gauge work? Strain gauges are popular for directly measuring strain. [Image Source] A strain gauge is a foil with an electrically conductive grid. As a strain gauge is stretched or compressed, the electrical resistance of the grid increases or decreases proportionally. The reason being that as the grid is stretched, the current has to travel a greater distance in a thinner conductor which both lead to increased resistance (and vice versa). Why use a strain gauge for vibration measurement? For more on how strain gauges work, check out HBM's article; but what makes them a good, and bad, sensor for measuring vibration? The good is that they are very versatile and accurate. They can be installed on virtually any surface and shape, and they measure both static and dynamic loads. They also measure strain directly so that calculating the stress in the material is fairly easy and accurate. Strain gauges are also very small, and lightweight. So they don't really alter the overall stiffness of the test specimen. And best of all, a typical strain gauge will cost only a few dollars to a few hundred for very high-quality ones. What's not to love?! Why wouldn't you use a strain gauge for vibration measurement? They are a pain in the butt to install! Take a look at a popular strain gauge installation tutorial - it's 20 minutes long to install these properly when you know what you're doing. I remember an intern at Mide many years ago exclaiming to me that he had successfully made a removable strain gauge - he just used double sided tape to apply it!... that obviously won't adequately adhere the strain gauge to the material. Mounting accelerometers are important but they just need to accelerate with the test instrument. For strain gauges, they need to be perfectly bonded to the material across the entire face to strain with the test article. The other challenge strain gauges pose is that the electronics necessary to amplify the signal and acquire the data are costly (upwards of $10K), and cumbersome. Strain gauges are awesome if you know what you're doing and have all the right equipment. But if you're reading this blog post, you likely aren't an expert in vibration testing and therefore I'd recommend steering clear of using strain gauges. Electromagnetic Velocity Sensor Velocity Sensor Suppliers Velocity Sensor Pros Velocity Sensor Cons Hard to find Measure velocity directly Very high-temperature range (> 700°F or 370°C) Not really manufactured anymore…
I almost didn’t include these in the list, but I know you may run across mention of them in your search for vibration sensor options. They operate by using the current generated from a magnet traveling within a coil. The advantage of these is that they measure velocity directly and they have a very high-temperature range.
But over the last 5 to 10 years piezoelectric accelerometers have improved in regard to noise, size, and durability. So now virtually everyone (except the energy industry in super hot applications) uses accelerometers and integrate the output to calculate velocity. For more on the relationship between acceleration, velocity, and displacement – check out our simple harmonic motion calculator.
Gyroscope (Angular Rate Sensor)
Gyroscope Suppliers Gyroscope Pros Gyroscope Cons Analog Devices
TE Connectivity
Qualtre Measures rotation
Typically MEMS so low cost Should be used with accelerometer to measure orientation
Gyroscopes, when used with accelerometers, provide absolute orientation information during a vibration test.
Where accelerometers measure linear acceleration, gyroscopes measure angular rate. Instead of an output in gs we get a rate value, typically displayed as degrees per second (°/s).
How does a gyroscope work?
Most gyroscopes now use MEMS technology and have three small resonating masses that get shifted as the angular velocity changes, utilizing the Coriolis effect. A much more detailed description is available from Analog Devices.
Why is a gyroscope helpful for vibration testing?
Gyroscopes provide a frame of reference one doesn’t have with an accelerometer alone (or even a bunch of accelerometers). Accelerometers measure inertial forces, so yes they can help provide a frame of reference in relation to gravity, but it gets messy (and near impossible) to keep that reference when your accelerometer is vibrating itself… which will typically be the case when doing vibration testing. An accelerometer can also get “disoriented” during events that have sustained static accelerations (like a banking aircraft) that can be misinterpreted as the gravity vector. The gyroscope, however, would allow the system to know the true course of motion.
Gyroscopes, when used in conjunction with accelerometers, help keep track of the orientation of your system. One wouldn’t typically use a gyroscope alone for vibration testing but with accelerometers, you’ll have a much more complete picture of the vibrating environment.
Non-Contact Vibration Sensors
enDAQ makes vibration data loggers (formerly known as Slam Sticks) that we market as easy-to-use, yet accurate and high quality, alternatives to traditional vibration measurement systems. In a moment of brilliance, a not-so-technical coworker of mine exclaimed that we could make it really easy to measure vibration if we can figure out a way to “measure vibration through the air!”
My first reaction was to suggest that “measuring vibration through the air” is impossible – in order to measure vibration, the sensor (or sensing system) needs to be mechanically attached to vibrate along with the test structure or device. But that is not actually the case…
Microphones or Acoustic Pressure Sensors
Microphone Suppliers Microphone Pros Microphone Cons PCB Piezotronics
Brüel & Kjær
Invense (PCB Mounted) No contact with vibrating structure
Supplemental information to accelerometers
Very rich frequency content Requires supporting electronics
Measures relative vibration amplitude
Microphones can provide a very detailed view of the frequency content in your vibration environment without altering it. [Image Source]
Sound is not often thought of as a way to measure vibration, but it should be! After all sound, by definition, is a vibration that travels through the air in the form of pressure waves.
When to use a microphone or pressure sensor for vibration testing?
Microphones offer a cost-effective means of measuring high-frequency vibration and is especially useful to determine how a system’s vibration changes with time. Health monitoring applications can greatly benefit from using a microphone on cost and simplicity. Microphones can also provide a very clear and accurate representation of the frequency content in your vibration.
Microphones aren’t limited to applications where cost is a concern; some acoustics applications will use high-end microphones for vibration testing and analysis. You’ll notice a lot of the accelerometer companies also offering high-end microphones. Acoustics is a major area of vibration testing and has very similar analysis, data acquisition, and sensor characteristics.
When not to use a microphone for vibration testing?
Microphones and acoustic analysis can be a great option for some applications; but if you need absolute shock and vibration data, not relative change, then microphones probably won’t work. They also won’t be able to analyze modal shapes and specific/discrete points along your structure. But again, they are very effective for overall frequency analysis.
Laser Displacement Sensor
Laser Displacement Suppliers Laser Displacement Pros Laser Displacement Cons KEYENCE
Micro-Epsilon
Acuity No contact with vibrating structure
Very accurate displacement data Measures relative motion to laser
Need’s clean and stable environment
High power consumption
How does a laser displacement sensor work?
Laser displacement sensors measure the distance between itself and a target – helpful for some vibration testing applications. [Image Source]
A laser displacement sensor uses triangulation with a transmitting and receiving lens. A laser beam is emitted down towards the target through a transmitting lens. The light then reflects back towards the sensor and is directed by a receiver lens to a receiving element. As the target moves closer and farther away, the angle of the reflected light changes (it’s focused on a different position on the receiving element).
When using a laser displacement sensor makes sense?
Displacement sensors can be preferred in some applications that prevent the use of accelerometers such as rotating components (although a data logger could be used), or when the accelerometer’s mass would too greatly influence the motion of the system. They also measure displacement directly which may be the true parameter of interest (not gs) for certain vibration testing applications.
When to avoid laser displacement sensors?
The downside to using these is that it’s measuring relative motion between two structures. These are near impossible to use in the field because a fixed mounting and distance is required between the sensor and equilibrium position of the vibrating structure. They can also be quite a bit more expensive (system cost over $5K) and complex than accelerometer-based systems. Also, displacement sensors should be avoided for shock testing for fear of damaging the sensors.
Eddy Current and Capacitive Displacement Sensors
Displacement Sensor Suppliers Displacement Sensor Pros Displacement Sensor Cons Lion Precision
Micro-Epsilon
KEYENCE No contact with vibrating structure
Very accurate displacement data Measures relative motion to sensor
relative motion to sensor Need’s clean and stable environment
High power consumption
Eddy current and capacitive displacement sensors measure the distance between itself and a target – helpful for some vibration testing applications. [Image Source]
These sensors have similar benefits and drawbacks as lasers for vibration testing. On the one hand, they offer a way to “measure vibration through the air” without altering your vibrating system. But they only measure relative motion, they need to remain fixed and measure the difference in motion of a nearby structure. So they typically are used only in the lab especially considering the fragility of the system (expensive sensors, wiring concerns, and power supplies).
Difference between eddy-current and capacitive displacement sensors?
Lion Precision does a much deeper comparison between the two sensor types than I could ever that’s worth checking out if you’re interested. But to summarize, capacitive sensors use a high-intensity electric field it generates. So long as the material of the target doesn’t change, the only dynamic variable that impacts the strength of the reflected field is the distance between the target. Similarly, an eddy-current sensor creates a magnetic field and measures the changing response of that field.
Vibration Sensing Systems
All the previous vibration sensor options discussed require the user to handle wiring, provide power, signal conditioning, and electronics to acquire the data. The next two options do all that for you in one, self-contained system. These make it much easier to do vibration testing for the general purpose user, but they often come in handy for advanced vibration measurement and analysis experts for initial testing.
Vibration Meters
Vibration Meter Suppliers Vibration Meter Pros Vibration Meter Cons Fluke
ExTech
Reliability Direct Very easy and quick to use
Provides go/no-go data instantly Not meant for dynamic events
Limited data capture and analytics
Vibration meters are a tool that enable you to get a quick overview of the vibration environment. [Image Source]
Vibration meters offer real-time vibration analysis in a handheld unit so that maintenance decisions can be made quickly in the field. They either wire to a traditional accelerometer or some even incorporate the accelerometer into the unit cutting down on wiring requirements and complexity. Vibration meters give RMS and peak-to-peak levels in real time, sometimes include the resonant frequency of the vibration. They also will typically have an algorithm to rate the overall vibration of your bearing or machine.
When to use a vibration meter?
Vibration meters are typically used in industrial health monitoring. A technician will routinely (fixed schedule or when he/she suspects a problem) inspect the machinery. The setup is very quick: just press the device to the machine (if it has the embedded accelerometer), read the vibration level and then make a decision if maintenance or repair is needed. For that quick go/no-go vibration testing of a piece of machinery, a vibration meter is unbeatable.
When not to use a vibration meter?
Vibration meters don’t allow the user to log long duration events (they may give you access to the last couple thousand points for some analysis). Vibration meters can also be a bit pricey at around $1,000 which typically won’t include the cost of the accelerometer (the Fluke 805 is over $2K that has the embedded accelerometer). If you are looking to do some more in-depth vibration analysis or any shock testing, a vibration meter is probably not your best option.
Vibration Data Loggers
Vibration Recorder Suppliers Vibration Recorder Pros Vibration Recorder Cons enDAQ
MadgeTech
MSR
Convergence Instruments Easy-to-use
Portable
Affordable Limited synchronization options
Limited sample rate and data quality (typically)
Vibration data loggers offer a cost effective way to capture vibration data quickly and easily. They are often used before setting up more complex systems and for some applications completely replace the “traditional” wired accelerometer based setup.
Vibration data loggers combine all the components necessary for most entry to mid-level vibration testing applications:
Embedded accelerometer(s)
Data acquisition and storage
Power with embedded battery
Signal processing and filtering (hopefully)
For a detailed list of vibration data logger options and a comparison of them (including our competitors) check out our post: Rating My Top 11 Vibration Data Loggers.
When to use a vibration data logger?
To put it simply – vibration data loggers are when you grimace at the complexity and cost of setting up a “traditional” accelerometer-based vibration measurement system.
Vibration data loggers are best for applications that need to do some testing quickly. They are very easy to set up (just tape or bolt to surface and press the button) so that an engineer (but you don’t need to be all that technical) is able to acquire vibration data quickly and easily. Everything is self-contained so vibration data loggers are also extremely portable – making testing in the field very easy.
A typical use case for a vibration data logger is when you are designing a product or system and need to get some test data from its intended operational environment (not all this data is readily accessible). For this application, you can set up the test, leave it for minutes or hours, then return to download the data and see what type of vibration and shock events occurred.
One can also use a vibration data logger when wiring is not feasible. This includes some ammunition testing (we’ve had customers put enDAQ sensors in missiles – hopefully they retrieved them and the data!), rotating machinery, the outside of an aircraft (one customer that I know about even flew with the sensor mounted to the wing with a bunch of duct sealing), etc.
Lastly, vibration data loggers are a good tool to use before setting up more complicated systems. We often have vibration analysts send a vibration data logger to a client to perform some initial testing before they need to travel to the location themselves. The initial testing will help provide some information on the type of environment so that appropriate advanced sensors can be used, and it may even help locate key areas to mount those sensors.
When to not use a vibration data logger?
Vibration data loggers are limited in two main areas: lack of synchronization, and a (generally) poorer data quality. Because it’s difficult to synchronize between units you won’t be able to do modal testing of large structures. That doesn’t mean that vibration data loggers aren’t time-stamped; they are. But the time stamp isn’t accurate enough (typically 100s of milliseconds when you may need less than a millisecond precision).
Vibration data loggers are also often thought of as having poor data quality. While that may be true for systems made over 10 years ago, sensing technology is improving and getting smaller. Not to mention, embedded electronics are also becoming increasingly more capable of performing the high-speed processing and data acquisition necessary.
That being said, sampling rates will be limited to 20,000 Hz for higher end data loggers and the noise floor will typically be higher compared to an advanced accelerometer.
Summary
If you’re still reading this post, hopefully, you have a better idea of which sensor is best for your application! If not, don’t hesitate to reach out to us and ask. And here’s that summary comparison table again for reference.
Sensor Type When to Use When not to Use Top Supplier Accelerometer General purpose shock and vibration Limited budget and access to necessary electronics PCB Piezotronics Strain Gauge Curved surfaces, when size and mass are important, need strain data Time or wiring constraints, need to measure acceleration HBM Velocity Sensor High temperature (> 700 °F) applications Hard to find, generally better to use accelerometer and integrate Gyroscope Orientation data is required Typically not used on their own, but with accelerometer Analog Devices Microphone or Pressure Health monitoring, determine vibration frequency To measure acceleration directly, determine vibration at known locations PCB Piezotronics Laser Displacement Measure displacement directly without altering your structure or product Outside of the lab, when power is a concern KEYENCE Eddy Current or Capacitive Displacement Measure displacement directly without altering your structure or product Outside of the lab, when power is a concern Lion Precision Vibration Meter Quick go/no-go diagnosis of machinery Transient events and longer than 15-second tests Fluke Vibration Data Logger Save time & cost, testing in the field (portability important) Modal testing, very fast sampling needed (> 20 kHz) enDAQ
Additional Resources
If you’d like to learn a little more about various aspects in shock and vibration testing and analysis, download our free Shock & Vibration Testing Overview eBook. In there are some examples, background, and a ton of links to where you can learn more.
Related Posts:
For more on this topic, visit our dedicated Vibration Loggers & Vibration Sensors resource page. There you’ll find more blog posts, case studies, webinars, software, and products focused on your vibration testing and analysis needs.
Ground Vibration Monitoring – BeanAir
Construction and industrial dynamic sources can produce environmental vibration problems for adjacent and remote structures. High vibrations and unacceptable dynamic settlements could disturb sensitive devices and people and even be the cause of structural damage. The dynamic sources, the geology at a site, and the condition of structures affect ground and structure vibrations. Each construction or industrial site is unique and requires consideration of specific approaches at the site for decreasing vibration effects of construction activities or industrial dynamic sources on surrounding structures. Monitoring and control of ground and structural vibrations provide the rational to select measures for prevention or mitigation of vibration problems.
Our wireless accelerometer comes with a great flexibility, user can easily pick and place this device on monitoring site. Coming with a very low noise (45 µg/√Hz), this device offers great performanace
X1 Ground Vibration Sensor
X1 Ground Vibration Sensor is a battery operated wireless sensor for measuring ground vibration from construction, earthworks, piling or demolition works.
It outputs calculated peak particle velocity in mm/s, as well as individual velocity from the x, y and z axis. It can be programmed to take measurements in one minute to daily intervals – or placed into continuous mode and output events that exceed threshold values.
The sensor is self-calibrating thanks to inbuilt algorithms. It can communicate via LoRaWAN, WiFi, Bluetooth or Cellular LTE and provide data outputs via AlphaX Cloud API, POST, MQTT or via LoRaWAN service provider.
Ground Vibration Monitoring
Ground Vibration Monitoring Mission Statement:
The Ground Vibration Monitoring website seeks to answer the most common questions pertaining to ground vibration monitoring in order to help the user determine…
What is ground vibration monitoring?
Who uses ground vibration monitoring?
How do ground vibration monitors work?
Where can I rent ground vibration monitors?
In addition, it provides information pertaining to recommended instruments, basic monitor setup, industry standards, and a page of posts containing frequently ask questions and troubleshooting.
What is ground vibration monitoring?
Ground vibration monitoring is the process of measuring and recording the movements in the ground using a seismograph. As vibration occurs at a source, a seismic wave travels causing soil and rock particles to move back and forth over very small distances. This is known as particle velocity. The vibration monitor measures the Peak Particle Velocity: the maximum speed of a particular particle as it oscillates about a point of equilibrium, caused by the traveling seismic wave. By measuring the Peak Particle Velocity in inches per second, operators indicate whether damage is likely to occur to surrounding structures.
Unlike large, permanently-mounted seismographs that measure earthquakes or other geologic events, ground vibration monitors are small and portable with the ability for programming specific parameters. Therefore, an operator programs the unit to specific parameters that only record during a given time period or only trigger a recording once a certain criterion occurs.
Generally, these monitors record man-made vibrations as opposed to natural seismic occurrences. To learn more about monitoring natural seismic activity, please visit the U.S. Geological Society Earthquake Monitoring page.
Who uses ground vibration monitoring?
Ground vibration monitoring records vibrations caused by traffic and construction projects as well as quarry and mining operations. Engineers and construction companies usually assess their ground vibration to make certain that machinery and construction work does not cross a threshold, causing structural damage to neighboring buildings and infrastructure. Likewise, quarry and mine operators monitor the vibration caused by blasts, compaction methods, and heavy machinery/equipment. In some instances, they use the monitors to measure the damaging air overpressure caused by a blast and fine tune their blasting techniques.
All ground vibration is of some concern. Most heavy construction projects centered in urban areas and industries involved in blasting require monitoring the ground vibration that they cause. However, that doesn’t mean that homeowners or businesses near these sites should not contract an experienced company to perform ground vibration monitoring. The ability to prove that ground vibration from an outside source caused or did not cause damage protects those that pay to conduct a survey. Ultimately, the reports from vibration monitors prove helpful in demonstrating whether vibration is great enough to cause concern or not.
How do ground vibration monitors work?
Ground vibration monitors use a transducer, also called a geophone, to measure vibrations. To properly measure these vibrations, securely couple the geophone to either the ground or a structure. This ensures that the geophones sense all the energy in the ground. Inside the geophone, a spring-mounted, magnetic mass moves within a wire coil when the ground vibrates. This produces an electrical signal proportional to the ground vibration velocity that the monitor records.
Ground vibration monitoring measures three types of ground vibrations.
The ground vibration monitor’s transducer is a triaxial geophone. This means it measures vibration on three planes. Transverse ground vibrations cause particles to move in a side to side motion. Vertical ground vibrations cause particles to move in an up and down motion. Longitudinal ground vibrations cause particles to move in a back and forth motion progressing outward from the source.
To receive good results and properly distinguish transverse vs vertical vs longitudinal vibrations, orientate the geophone correctly. The arrow on the geophone must be visible; otherwise, the geophone is upside-down. Point the arrow on the top of the geophone towards the seismic source. Make certain the geophone is as level as possible. Finally, fasten the geophone securely to the ground or structure. Most geophones come with spikes that stick into the ground. If the ground or surface does not permit spikes, the unscrew the spikes and the couple the geophone to the surface by placing a heavy sandbag over it.
Do ground vibration monitors measure anything else?
Because monitors often record blasts in the quarry and mining industries, microphones are sometimes used to measure air pressure. This damaging air pressure is commonly referred to as an “air blast”. By measuring air pressures, these industries determine the effects of the air blast energy on structures. The monitors connect to two different types of microphones: Linear “L” microphones or “A” weighted microphones. Predominantly, operators use Linear “L” microphones to measure the effect of low frequency air pressure on buildings whereas “A” weighted microphones measure noise levels people consider an annoyance because it’s a scale similar to the human ear.
Where can I rent ground vibration monitors?
Several environmental equipment or geophysical instrument companies rent ground vibration monitors. The Ground Vibration Monitoring website recommends K.D. Jones Instruments.
K. D. Jones Instruments rents Instantel Minimate Plus and Blastmate III units for reasonable rates. These ground vibration monitoring units arrive fully charged as well as factory calibrated. Generally, factory calibration occurs once a year for each unit. Moreover, K.D. Jones Instruments checks every unit for functionality before sending an item to a customer. All in all, over 25 units are available and ready to rent. Typically, vibration monitors are sent with geophones with a 2 to 250 Hz range. Moreover, they conform to use with the ISEE (International Society Of Explosive Engineers) standard.
In addition to the vibration monitor, accessories such as DIN geophones, waterproof geophones, extension leads, alarm boxes, field printers, uninterruptible power supplies, or linear microphones are available upon special request.
Find help with Minimate Plus and Blastmate III setup at VibrationMonitoringCourse.com.
Remote Ground Vibration Monitoring Systems
Other applications
When carrying out construction works which may produce vibration, all potential receptors must be considered, with particular attention paid to occupiers and users of buildings, hospitals or laboratories, as well as cosmetic or structural damage to buildings or heritage sites.
Companies are already requested to take care planning the sequence of works in order to minimise the transfer of vibration to neighbouring properties, and in some cases project managers are instructed to monitor ground borne vibrations, react and adjust work methods to ensure vibration levels are kept below specific levels.
As available space becomes tighter it will be imperative to protect surrounding properties from the effects of excessive vibration during such works, particularly in cities across the UK.
Piles are the permanent foundation support to so many different structures throughout the UK, so it is of great importance to know the likelihood of disruption that could be caused through installing piles in order to minimise or alleviate it altogether. An increasingly important aspect of project management during construction work, is to understand the impact of ground-borne vibration, on the surrounding community.
Most susceptible to damage from ground vibrations are fragile and historic buildings. A building’s response to ground-borne vibration is affected by various different factors and while a concern doesn’t always mean that there’s potential for damage, without an auditable trail of vibration data it can be difficult to link damage with a particular cause.
As available space becomes tighter it will be imperative to protect surrounding properties from the effects of excessive vibration levels arising from demolition works, particularly in cities, as well as on sites near historic building and sensitive structures such as railway viaducts, railway lines, hospitals, server rooms, electrical sub stations and gas mains.
Sensors and Shakers for Ground Test
Sensors and Shakers for Ground Vibration Testing
GVT (Ground Vibration Testing) uses TEDS ICP® accelerometers, cables, patch panels, and signal conditioners for modal analysis response measurements. Shakers and Modally Tuned® Impulse hammers are utilized for structural excitation during these tests. TEDS Dynamic Force Sensors, Accelerometers, and Impedance Heads measure the input forces placed on the structure.
View our Prezi below on large channel systems to help determine which product may best fit your testing needs. Download the PDF document for suggested model numbers.
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Ground Vibration Sensor
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