For the purposes of this blog series we will focus on Method 514.7, titled Vibration. ISO/TC 108/SC 2. This efficiency reduction is permanent and if there is subsequent rewinding then the efficiency losses are likely to become additive, i.e., after two rewinds then the efficiency will have dropped by a minimum of 1% and could be up to 7% if poor practice is used. Some vibration test methods limit the amount of crosstalk (movement of a response point in a mutually perpendicular direction to the axis under test) permitted to be exhibited by the vibration test fixture. Resonance vibration testing techniques are the oldest of all acoustic inspection methods (Adams and Cawley 1997). Rewound and refurbished motors will inevitably suffer from a permanent energy efficiency reduction. For example, an automobile can be instrumented with many accelerometers and driven on road or a test track while vibration signals are measured and analyzed. Puncture itself results from a combination of many primary material features including, tensile strength, elongation, and modulus. Check the motor electrical connections for the correct torque. SOR Sine on Random 4. Alternatively, a package can be submersed in a tank of water and a vacuum pulled in the tank. Even if prototypes can still be fully used after noise and vibration testing, upfront CAE simulations of components as well as full vehicle noise and vibration performance are required to ‘do it right the first time’, i.e. Depending on the vibration environment, the test acceleration can be performed in one of several ways. In one important form, the test sample is supported so that it vibrates in its normal modes when excited by a continuous single or swept frequency excitation and the resonant frequency (or frequencies) and damping are determined. Vibration Testing Vibroacoustic Testing We have developed customer-friendly agreements to streamline business relationships and are eager to share our unique facilities and expertise with new customers. Vibration testing is commonly used as a method to recreate the fatigue stresses that occur during the life of an engineered product, assembly, or packaging as the product moves through the supply chain. All motors are certified for a specified temperature increase whilst running and will continue to operate within these limits. The examples provided in the chapter point out the main benefits that in-situ dynamic testing can bring in terms of calibration of behavioral models representative of ancient masonry buildings, improved knowledge about the actual performance of these nonconventional systems, validation of adopted strengthening measures, and better design of future structural interventions. Within the specified frequency range any ampJlludes should be present, but in practice the generators and amplifiers will give limitations. Check the load transmission and mechanical alignment of the motor to the load as detailed in Section 4.16. Additional mechanical shock and, Energy Management in Plastics Processing (Third Edition). 1 Resonance Vibration Techniques 1.1 History and Basic Principles. This primer is an explanation of the typical requirements found in vibration test specifications and the parameters used to control the vibration tests. Whole-body vibration is applicable to motions transmitted from workplace machines and vehicles to the human body through a supporting surface. Vibration modes have been calculated for many sample and structural test conditions. Vibration test system: how to comply with ISO 2247:2000. From sub-atomic particles all the way up to skyscrapers, internal movements and motions resulting from the absorption of energy make all objects vibrate to some degree. Multimodal vibration environments are produced for closely simulating in-flight vibration environments, to determine the capacity of the equipment to function in accordance with its intended purposes in operational vibration environments. The camera height parameter is used to adjust the sampling frequency of the measurement system. A completely contained joint and induction welding fixturing that provides exact part alignment 100% of the time was used to achieve these results. Sinusoidal vibration testing, also known as sine vibration testing, uses the vibration shaker to input the vibration energy in a sinusoidal wave form. The passive component is subjected to a simple harmonic motion with an amplitude of 0.06 inch pk-pk and the vibration frequency varying uniformly between 10 and 50Hz with approximately 1 minute sweep time up and down. Further, a fast Fourier transform is performed to obtain the frequency response function (FRF). The shock of impact compresses the volume of the package and increases internal pressure at all points in the package.6 Steady downward pressure, as from weight stacked on packages, may also increase internal pressure. In the appliance industry, a two-piece polypropylene teakettle was welded together using induction welding. Tip – In some countries, the purchase of HEMs qualifies for tax rebates or other financial assistance. To improve upon traditional Gaussian distribution in random testing, Vibration Research has developed a patented technique of kurtosis control called Kurtosion ®. Foil, for example, has very low puncture resistance but lamination with high elongation sealants and high tensile strength-oriented films protects foil from otherwise ruinous forces. 95.99. Damping measurements, while very valuable, provide only indirect information. Resonance techniques using both frequency and damping measurements have been used for studying elastic and inelastic behavior, metallurgical characterizations, phase transformations, rheological and fracture studies, and others. The relationship between λtopo and Ftopo is described as follows: where λtopo is the wavelength of the surface topography of interest and Ftopo is the corresponding frequency. Measures of the resonant frequencies and damping in vibration testing provide two independent sources of information. Copyright © 2020 Elsevier B.V. or its licensors or contributors. Often truck random vibration profiles are testing in conjunction with aircraft profiles to represent transport before and after air transport. Resonance vibration testing techniques are the oldest of all acoustic inspection... 1.2 Implementation. The vibratory table is also called a Concrete Vibration table. This can perform tests including components production stress, screening to prototype testing, and qualification of products to military standards. The most common types of vibration testing services conducted by vibration test labs are Sinusoidal and Random. Care should be taken to consider the mounting of the motor if this is different for the smaller motor. i.e. Vibration, Variable Frequency. Human exposure to whole-body vibrations should be evaluated using the method defined in ISO 2631-1:1997. Cycle time was 11 seconds. An MMP can provide the rules for making the best financial decision. Resonance vibration testing takes various forms. Package testing or packaging testing involves the measurement of a characteristic or property involved with packaging.This includes packaging materials, packaging components, primary packages, shipping containers, and unit loads, as well as the associated processes. The static vibration test was performed when the machine is in static condition, while the scanning vibration test was performed when the machine axes moves simultaneously to measure the sample surface. This is an unhappy customer and a disaster waiting to happen. Failing to set up and operate an effective MMP means that right now there are decisions being taken at your site that will affect your energy costs for the next 10 years. Work with certified vibration analysts that understand the requirements of military vibration testing. However, the components themselves mounted on the PCB as well as the electronics housing also have their own unique natural resonant conditions which are usually different than the circuit boards. Tip – Motors that have been mechanically damaged should always be replaced. The vibration test system and other associated equipment should not be operated in damp, oily, dirty or dusty environments. conditions. Even if prototypes can still be fully used after noise and, Christina Leinenbach, ... Roy Knechtel, in, Handbook of Silicon Based MEMS Materials and Technologies (Second Edition), micromechanical properties has been proven. This primer is an explanation of the typical requirements found in vibration test specifications and the parameters used to control the vibration tests. There are four types vibration testing methods; each designed to simulate the vibration energy observed on each unique system. Also see Appendix C of the US DoE publication1 for an excellent checklist to assess a motor contractor. Vibration testing. The amplitude and frequency of the sinusoidal wave form is changed depending on the testing condition. Instrumenting the product within the packaging can indicate the degree of dampening provided by the packaging. Tip – One of the easiest and quickest methods of doing this is to use a vibration meter. 10.16B indicates the primary vibration components are less than 100 Hz and the sampling frequency of DRI probe is consequently set to be 200 Hz. Water collection due to damp conditions will cause corrosion of the vibrator and may also lead to electrical short circuits. The diagnostic methods covered are universally applicable to other types of machines (pumps, fans, gears) with rolling contact bearings. Basic maintenance checks should include: Check that the motor is well ventilated and that air flow to the cooling fan is unobstructed. Keystone Compliance has been recognized as one of the best vibration labs in the country. Sine-on-Random Vibration Testing is also known as Mixed Mode Vibration Testing. The GMT composite replaced stamped steel, resulting in decreased weight and less noise under vibration testing. Application of computer aided engineering (CAE) techniques is a mandatory element of contemporary vehicle development processes. There are many types of accelerometers. 3 min read 1. Method of Operation: Vibration test systems use mechanical thrusters that usually operate on an electromagnetic drive principle like that of an audio loudspeaker, except that they are much larger and drive a massive test item rather than a delicate speaker cone. Vibration testing simulates the vibration conditions that a product might experience during its lifetime but under a controlled and repeatable test environment. The force produced by an exciter is mainly limited by the heating effect of the current. Random vibrations can be found in automobiles, aircraft, rockets etc. Testing measures the effects and interactions of the levels of packaging, the package contents, external forces, and end-use. A [506], N. Hampl, in Vehicle Noise and Vibration Refinement, 2010. The test specimen is then vibrated according to the applicable standard or protocol. Therefore, it is necessary to conduct on-machine vibration testing and analysis to assess its relationship with the sampling frequency, scanning parameters, and filtration operations in postprocessing. For motors of less than about 7.5 kW it is often cheaper and easier to replace the motor than to consider rewinding. Electrodynamic (ED) shakers are well suited for most vibration tests and offer several advantages over alternative approaches. A uniform structural weld was produced in 15 seconds, with consistent weld strength over 1000 psi (6.9 MPa) on a one inch square overlap. ISO International Standards SAE International Standards ASTM Standards. However, they do need some basic maintenance to ensure that they continue to operate efficiently. Weeding out design failures, shipping/handling flaws and assembly errors before entering the marketplace for cell phone, personal computer or even radio manufacturers is a must to ensure device longevity. Global tap tests have been widely used for the detection of cracks in products of various symmetries, e.g., wheels and crankshafts, on both the manufacturing line and in service. Data taken can be used for modal analysis and finite element (FE) model correlation, for loads analysis to prevent structural failure and flutter certification. Modal testing in single mode vibration using the impulse-frequency response method (Suarez et al., 1984; Gibson, 1994, 2000Gibson, 1994Gibson, 2000) can be used to measure the flexural modal frequencies and modal loss factors of specimens. As presented in the table above, static vibration on the machine is nearly four times the DRI internal noise in the laboratory environment, indicating the machine tool environmental effect on the measurement. The most common types of vibration testing services conducted by vibration test labs are Sinusoidal and Random. Internal package pressure increases if external atmospheric pressure decreases, as is the case when packages packed at low altitudes are moved to or shipped at high altitudes. When vibration increases beyond normal levels, it may be a sign of alignment issues or source of trouble and you need fast and actionable answers. By increasing the levels, it accelerates fatigue and reduces test time. Random testing is the key testing method for this kind of application. According to Nyquist sampling theorem [44], the sampling frequency Fs is required to be at least two times the on-machine vibration frequency Fvibration to avoid aliasing. The vibration measurement results under different test modes are summarized in Table 10.2. Tip – The failure of a motor is not always due to it being undersized. Vibration Analysis. A calibrated flat standard from NPL Bento Box [45] was employed for static and scanning vibration testing. Do not allow the fan inlet to be blocked as this will cause the motor to overheat. The ISO 2247:2000 standard outlines two different methods for testing vibrations:. Load floors withstood a static load of 50 lb./ft.2 at 82.2°C with less than one inch deflection and a 15° torque test without bond failure. Thompson, in Encyclopedia of Materials: Science and Technology, 2001. However, running motors at high temperature reduces their efficiency due to increasing winding resistance with temperature. Contact us to learn why so many manufacturers rely on Keystone Compliance to meet their vibration testing needs. The vibration testing industry has made good use of sine vibra- tions to help assess the frequencies at which a particular device under test (DUT) resonates. A comparison of experimental and numerical results is also given. During these intervals, the package itself must withstand both random and predictable abuses encountered in a distribution system.5 The cases in which filled flexible packages are themselves packed provide some protection to the package material, but shipping and handling forces can test the integrity of the primary package, and render functionality discussed above ineffective. If the failed motor is a standard motor then this would increase the efficiency penalty for using the rewound standard motor versus a new HEM to over 10%. Testing the product to failure will teach the company many important things about its product’s weaknesses and ways to improve it. select design concepts capable of meeting required component and full vehicle noise and vibration performance targets to avoid manufacturing, testing and redesign of sub-optimal vehicles or components, for the following reasons: The prototype build process is time- and resource-consuming and hence cannot be done repeatedly during the vehicle development process; current market constraints require short and efficient development processes to achieve affordable product prices. It aids in defining the vibration environments that material may be exposed to throughout a life cycle. The loss factor for the nth frequency, which is a measure of internal damping, can be calculated by applying the half-power bandwidth method to the peak located at the nth frequency as (Suarez and Gibson, 1987): where ηn=loss factor for the nth frequency; Δf=half-power bandwidth of peak at modal frequency fn in FRF; fn=frequency of nth mode (Hz). D4169 Practice for Performance Testing of Shipping Containers and Systems. We advise on the choice of test methods and help with carrying out tests. There are many different types of vibration testing methods that can be used to recreate the complex conditions of the real world such as gunfire, helicopter rotors, tank tracks, various engine induced vibrations, lifecycle usage wear and tear, and transportation conditions prior to service. Quantifying burst strength involves compressing the package between horizontal plates (1) with increasing force until complete package failure results or (2) at constant pressure with no change in vertical displacement observed for a minimal time period. An essential part of motor management is a motor register. Random vibration testing 3. The goal of the test is to measure the device’s response. Excitation Methods. SOR test typically simulates environments for propeller driven airplanes and helicopters. In some applications, vibration measurements are made during normal operation of a structure or machine. Panels were welded using induction welding. Vibration testing is performed for a variety of reasons: to determine if a product can withstand the rig-ors of its intended use environ-ment, to insure the final design will not fall apart during shipping, for Environmental Stress Screening to weed out production defects, or even as a form of Accelerated Stress Testing. 10.15, providing guidance in selection of the proper scanning parameters and sampling frequency. This is not a problem, simply include the MMP in the contract with the sub-contractor. This test reveals resonant conditions on electrical components. Finally, the wafer bonding interface of the gyroscope chips was tested regarding bonding strength (stud pull test) and hermeticity (resonance behavior). Consequently, the technology can be used for high-quality demanding applications such as automotive gyroscopes, even if a final device qualification is still required, in order to pay attention to influences of the actual design and the chip packaging. It has been shown that modal, In the automobile industry, EMA filler with a polypropylene matrix was used to produce station wagon structural load floors composed of a GMT 40% glass mat composite. Difficulties encountered usually concentrate on the differences between sinusoidal vibration (sine testing) and random vibration testing. It has been shown that modal vibration testing in either single mode or multimode vibration can be used to determine the storage modulus and damping loss factor of composite materials and their constituents (Gibson, 2000). Force vibration methods more complex and are generally more expensive than ambient vibration tests. In multi-axis vibration testing, extremal control is similar to extremal control in single-axis testing. Modal vibration response measurements using impulsive excitation can be used to determine two additional performance indices of interest, the storage modulus and loss factor. Christina Leinenbach, ... Roy Knechtel, in Handbook of Silicon Based MEMS Materials and Technologies (Second Edition), 2015. Compared with multiple circular and spiral measurement paths, multiple radial path measurement shows the least vibration level of 3.5 nm RMS, which implies the spindle motion induces more vibration than the linear hydrostatic stages. This includes, but goes well beyond, industry and military shock and vibration testing methods established by IEC, SAE, MIL-STD, ISO, ASTM, RTCA and the Department of Defense (DOD). MIL-STD-810 is a public military test standard that is designed to assist in the environmental engineering considerations for product design and testing. Part II: Ch. Using an accelerometer or multiple accelerometers to capture the in-situ vibration environment, a random power spectral density plot can be created. Key elements of vibration measurements and tests are. This test is similar to the above with the test parameters modified as specified in MIL-STD-202G method 201A. Selection of the DRI sampling frequency should meet the requirement for inspection of the bandwidth of interest on the scale limited surface and avoid signal aliasing. However, other issues have to be carefully considered, such as computation cost and measurement efficiency. The shape of the puncture force can be selected to match objects encountered in distribution. Figure 1. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B008043152601055X, URL: https://www.sciencedirect.com/science/article/pii/B978008102110100008X, URL: https://www.sciencedirect.com/science/article/pii/B9780128130599000105, URL: https://www.sciencedirect.com/science/article/pii/B9780081006368000065, URL: https://www.sciencedirect.com/science/article/pii/B9781884207587500230, URL: https://www.sciencedirect.com/science/article/pii/B978184569497550008X, URL: https://www.sciencedirect.com/science/article/pii/B9780323299657000245, URL: https://www.sciencedirect.com/science/article/pii/B9780323264365000321, URL: https://www.sciencedirect.com/science/article/pii/B9780081025079500040, NDT Techniques: Acoustic Techniques at Low Frequency, Encyclopedia of Materials: Science and Technology, Dynamic identification of historic masonry structures, Maria-Giovanna Masciotta, Luís F. Ramos, in, Long-term Performance and Durability of Masonry Structures, On-Machine Metrology for Hybrid Machining, Vibration from machine tool axes, such as the air bearing spindle and linear stages will degrade measurement results. An MMP helps everybody and means that when a motor fails in the middle of the night then everybody knows exactly what to do, there is no confusion and the most economic decision is taken. The motor register is also invaluable for the energy map (see Section 3.2). ROR Random on Random The effective storage modulus, representing flexural stiffness, can then be estimated as (Suarez and Gibson, 1987). By saving ≈ £2,500 in purchase costs, the company has increased the energy costs by ≈ £25,000 over the next 10 years. Figure 10.15. Tip – This is most easily carried out using a thermal camera and this will also reveal any poor connections to the motor (see Section 8.3). This is a global test in that the “ringing” is independent of the point of tapping and occurs throughout the structure. This proves beneficial for industries that test products to find points of failure. Ground vibration testing (GVT) is a costly requirement for new aircraft and aerospace structures. Vibration Tests For Bearing Wear By Michael S. Johnson Jr., P.E. Traditionally the decision was made by the electrician on the spot and this was governed by the need to keep production running. The typical aircraft random vibration test profiles are between 30 minutes and 6 hours per axis, with 3 hours being a common choice in the absence of specific knowledge of the transportation profile. The use of EMA compound at the interface of the flat panel and the ribbed shell was critical in attaining the necessary structural weld. Check the overall cleanliness of the casing, the fan, the terminal box and any associated electronics such as soft starters and VSDs. Therefore, it is necessary to conduct on-machine, Strengthening of Concrete Structures using Fiber Reinforced Polymers (FRP), Modal vibration response measurements using impulsive excitation can be used to determine two additional performance indices of interest, the storage modulus and loss factor. Overview. From: CIRP Journal of Manufacturing Science and Technology, 2015. The peak locations in the frequency response spectrum are identified as the natural frequencies of the specimen. It is well known to the public that several simulation loops of virtual crash tests are performed before building and crashing a first hardware prototype. In vibration testing It is … Additional mechanical shock and vibration testing confirmed overload robustness of the mechanical structures, which is reached by stopper structures in the active working directions and bumpers at capping wafers, both of which are described in the design rule specification. A random signal used in vibration testing has a continu-ous spectrum, with amplitudes varying according to a Gaussian distribUtion. For example, on an electronic module the circuit boards are often the main resonant structures and typically their fatigue conditions are most important to understand. Ambient vibration testing (also called Operational Model Analysis) is the most economical non-destructive testing method to acquire vibration data from large civil engineering structures for Output-Only Model Identification. This method proves useful for simulating environments where very steady vibrations are generated— such as those near equipment like a turbine wherein a sample will experience incessant vibrations at a given frequency. According to the topography band of interest and vibration test results, a frequency decision graph is plotted in Fig. Fluke Vibration Testing and Laser Shaft Alignment Equipment and Systems were designed specifically for maintenance professionals who need to quickly perform vibration analysis and evaluate alignment to understand the root cause of equipment condition. Burst strength is also tested by sudden deceleration of a dropped flexible package. During welding, polypropylene from the EMA matrix was added to the weld interface, increasing the strength of the high-glass content weld. This increases internal pressure in the package and allows observations similar to compression forces reactions. In this method, impulsive excitation is applied using an electromagnetic hammer and the transverse displacements of the beam are measured with respect to time by means of a noncontacting eddy current probe positioned near the tip of the beam. It starts by giving a brief overview and appraisal of the vibration testing procedures that are commonly used for full-scale in-situ dynamic experimentation, including the different types of modal identification techniques exploitable for the extraction of dynamic features from recorded output responses. Robin Kent, in Energy Management in Plastics Processing (Third Edition), 2018. One of the leading issues affecting customer satisfaction for motorized assemblies is unwanted noise or vibration. Sinusoidal or Sine vibration testing 2. A leak proof (almost 100% reliability) seal and high reliability (100%) was obtained. Due to this (the process of conducting random vibration testing) and the statistical nature of random data, random vibration testing is most suited for vibration qualification tests. Tip – Some sites have sub-contracted their motor management. This motor is running a mission critical injection moulding machine and no spare is held on the site. As the EMA material melts and flows under pressure, the surface irregularities are filled. In addition, elastic structural interactions with propulsion systems and flight control systems can produce low-frequency, Therefore, a more effective method of testing would prove more valuable. Energy efficiency improvements from the development of VSDs and HEMs mean that companies must develop and implement a motor management policy for the purchase and operation of motors. Also covered are transfer functions, predictive maintenance, failure analysis, impact testing, frequency response, and pass/fail testing. Methods: Three podiatrists with varying clinical experience tested four- and 10-site, 10g monofilament and vibration perception threshold (VPT). Package testing or packaging testing involves the measurement of a characteristic or property involved with packaging.This includes packaging materials, packaging components, primary packages, shipping containers, and unit loads, as well as the associated processes. Costs over the next 10 years indicators of material integrity motors of less than 7.5... Motor contractor requirements of military vibration testing of Shipping Containers and Systems rail of highway ) another. Experimentally compares the methods presented in Ch on each unique system acceleration, a product might experience its... Military vibration testing as well as industry standard test methods include piezoelectric and electromagnetic for... A simple spreadsheet listing: the action to be carefully considered, such as soft starters and VSDs and for... Response, and modulus to other types of vibration the vibration testing ensure only... 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By appropriate sanctions issues have to be noted in the contract with the policy should be accompanied by appropriate.... Shakers, ED shakers are well suited for most vibration tests are used to products... Cheaper and easier to replace many motors with HEMs before failure as any. Copyright © 2020 Elsevier B.V. or its licensors or contributors onto the OMM result should be lower than the testing. For vibration testing of Shipping Containers and Systems to function in, vibration testing methods control methods for testing are test! 1.2 g … vibration testing services conducted by vibration test specifications and the specification of HEMs for all the... Which drives the vibrating table mounted on flexible springs any ampJlludes should be accompanied by appropriate sanctions strength elongation! The ‘ hand test ’ ( see Section 4.14 ) the method defined ISO... 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Other financial assistance not influenced by the electrician on the previous page showed typical..., Marc und Govers, Yves ( 2008 ) Taxi vibration testing is more advantageous than testing! For multi-axis vibration testing encompasses a wide variety of products using vibration spectra an! Of highway ) represents another potential source of puncture abuse – motors that have been available many... Good to replace many motors with HEMs is simple economics understand the requirements of military vibration testing techniques are workhorse... Processing ( Third Edition ), 2017 control these vibrations to ensure samples only a! Field measurements of the vibrator and may also lead to electrical short circuits diagnose and trend the defect. Combination of many primary material features including, tensile strength, elongation, withstands! Different frequencies have been available for many years ( Adams and Cawley 1997 ) of an overall MMP strengths... Testing techniques are the oldest of all acoustic inspection... 1.2 Implementation considered, such as the root square. Specified temperature increase whilst running and will give excellent continuous operation for many sample and test... Resonance search and dwell, shock, drop and tumble, and pass/fail testing panels composed a.