The machine produces the shock pulses using compressed air to force the platform to impact on the elastomer pads half sine programmer padswhich are placed between the platform and anvil of the impact area to produce half sine pulses, lead pellets are placed to generate. The shock response spectrum is a useful tool for estimating the damage potential of a shock pulse, as well as for test level specification. Beyond the more basic shock response spectrum, a look at the pseudo velocity shock response spectrum may be a prudent exercise ifwhen designing a system to survive shock. Choose a half sine acceleration pulse whose srs envelopes the expected response of the shock mounted item. It can be used individually or in conjunction with other applications as part of tailored workflows. Cam operated bounce test for transportation evaluation of. Effect of damping on shock spectra of impulse loads. Note that the shock response spectrum amplitude is 0. Shock response spectrum of halfcycle sine pulse excitation.
Introduction shock response spectrum srs analysis was developed as a standard data processing method in the early 1960s. The shock in figure 2 is approximately 150 g peak acceleration with a duration of 11 milliseconds. I suggested that the frequencies that are generated by the shock pulse as i had been told were up to 1duration, so for a 6ms duration half sine pulse we would excite frequencies up to about 167hz. The purpose of this report is to explain the shock response spectrum and to give a. The shock response spectrum is particularly suited for analyzing pyrotechnic shock. No it is not, however if my only two choices for test are 12 sine or tps, ill take tps every time. Fft of shock mechanical acousticsvibration engineering. The dynamic amplification factor daf of each mode was accounted for when the shock spectrum was derived.
The edm vibration visualization feature is available in edm vcs software all test types, including mimo vcs. Pulse types include half sine, haver sine, terminalpeak sawtooth, initialpeak sawtooth, triangle, rectangle, trapezoid. Response of a singledegreeoffreedom system to a halfsine force input pulse. The reason is that if you were to perform an analysis of the energy distribution of those two pulses such as shock response spectrum you would find that the energy of the shock is much more evenly distributed across the frequency band with the tps. The diagonal displacement dotted and acceleration dashed levels have the same 12510 spacing as used for the velocity axis. Also, note that the initial slope of the spectrum is 6 dboctave. However, i do not see how to see up the gs vs time half sine shock pulse.
Shock test machine shock test system shock pulse type. Tarang kinetics a leading manufacturer of shock test machine. Figure 2 shows a typical half sine shock performed by des. Shock response spectrum srs analysis was developed as a standard data processing method in. The shock response can also be simulated using direct transient analysis. Perform transient analysis of half sine shock wave at critical frequency in the vertical direction i. This program calculates the shock response spectrum for a base input, where the base input is in the form of an acceleration time history. Modal analysis modal analysis is the logical next step of vibration testing and looking at response spectrums. The shock response spectrum for the acceleration data in figure 3 is plotted below. I came across an excellent paper describing the shock response spectrum srs by tom irvine titled, an introduction to the shock response spectrum. Select from halfsine, haversine, initialpeak sawtooth, terminal peak sawtooth, triangle, trapezoid and square pulse shapes.
When the analytical halfsine pulse is applied to the fem, a response acceleration transient is computed for points around the structure where components are mounted. The duhamels integral method based upon linear force variation over time step has been. To capture the full shock spectrum, this analysis must be performed for each natural frequency that has significant mass participation. The shock response spectrum is a graphical representation of an arbitrary transient acceleration input, such as shock in terms of how a single degree of freedom sdof system like a mass on a spring responds to that input. Its origin probably dates from civil engineering and the problem of seismic excitations, i. Calculation of a shock response spectra acta montanistica slovaca. Workshop 9a shock response spectrum mscnastran102 exercise workbook 9a3 model description. A vibration control feature used to synthesize a specified shock response spectrum srs to measure a payloads resistance to shock damage. A half sine shock impulse has the shape of a half sine wave.
With standard shock test selected, srs analysis of response waveform is also possible. The three component waveforms available in testlab are wavelet, damped sine, and chirp. The horizontal axis shows the natural frequency of a hypothetical sdof, and the vertical axis shows the peak. This was calculated using the accelerometer time data from figure 2. It is possible to combine the shock response spectrum of several environments to get an enveloped damage potential of different shocks. This page offers tutorials which explain the shock response spectrum, as well as software tools for implementing this function.
Aug 29, 2019 a shock response spectrum srs is a frequency based function that is used to indicate the magnitude of vibration due to a shock or transient event. A halfcycle sine pulse acceleration time history is defined with maximum input acceleration equal to and duration forced vibration phase for the time period from to. I only see the options to set up a frequency curve and only two points. Drop table velocity and rebound spring displacement for a halfsine shock test.
Sep 28, 2010 no it is not, however if my only two choices for test are 12 sine or tps, ill take tps every time. Classic shock control vibration testing crystal instruments. The shock environment is quantified through a transformation from the time domain acceleration response, in units of g 32. How to judge severity from a shock response spectrum.
The horizontal axis shows the natural frequency of a hypothetical sdof, and the vertical axis shows the peak acceleration which this sdof would. Shock response analysis and shock response synthesis. Calculate the expected response of a shock mounted test item or measurements from field tests may be used and calculate a shock response spectra srs. Elastic response spectrum for elcentro earthquake california, may 18, 1940, ns component chopra 2012. I am trying to do a similar analysis, a half sine shock pulse on a structure. What is shock response spectrum srs a shock response spectrum srs is a graphical presentation of a transient acceleration pulses potential to damage a structure.
Srs generation supports many generation techniques including linear and exponential chirp, wavesyn, burst random, linear and exponential chirp on burst random, enveloped random, burst sine, or iterate from user waveform. Shock response spectrum of symmetrical triangular pulse excitation. The paper will deal with employing signal analyzer, the software. A shock pulse can be characterised by its peak acceleration, the duration, and the shape of the shock pulse half sine, triangular, trapezoidal, etc. The shock response spectrum is a method for further evaluating a mechanical shock. Maximum equivalent static deflection under shock can be determined from shock response spectra as follows. Up to 511 channels for monitoring and time data recording. Further, the dynamic magnification factor dmf in the shock spectra is maximum for rectangular pulse followed by halfsine wave and triangular pulse, for a given magnitude. However other engineers in my company say that the 6ms is only half the sine wave and therfore the total cycle is of 12 ms duration for. A half sine acceleration transient applied to a base frame structure simulating a drop shock event. Srs intro paper vibrationdata srs blog post link it includes several equations derived to obtain the response. Shock response spectrum of a halfsine impulse interval of 11 ms.
Runs a shock pulse defined by a frequency vs g peak table. Vibration testing, vibration analysis and mechanical shock help attune automotive products for structural soundness and paramount vehicle perception using methods such as resonant searches and dwells, fixture resonance evaluation, custom fixture design and fabrication, reproduction of sample road andor event data, shock response spectrum srs. Shock response spectrum of half cycle sine pulse excitation. The shock response spectrum srs allows to estimate transient acceleration signals in terms of a maximum response of a dynamic vibration system. With the help of ghis shock response spectrum software, several shock. A common misunderstanding is to regard the half sine shock pulse as having a discrete frequency which would be the case if it were extended to a full sine pulse. Classical shock testing delserro engineering solutions. Shock response spectrum srs analysis was developed as a standard data. The 50g acceleration level and 20mm displacement level are highlighted in red and green, respectively. For a 1,000g 5msec classical haversine shock the solution at.
Development of shock spectra for different pulse shapes. Development of shock spectra for different pulse shapes using. Shock response spectrum srs analysis was developed as a standard data processing method in the early 1960s. Understanding the use and applications of shock response. Shock response spectrum analysis introduction shock response spectrum srs analysis was under development as a standard data processing method in the early 1960s.
This option provides fast and efficient structural model generation and full 3d visualization of the online vibration pattern on the structure under. Note that this approach typically results in an overtest at the lowest frequencies. After the halfcycle sine pulse, zero acceleration is specified for time period from to free vibration phase. Request a quote srs synthesis is used to evaluate the shock resistance of the dut device under test. Of shock response spectrum method claudie hutin data physics france introduction definition of the shock response spectrum shock tests are performed to verify that a structure or a device can support transient vibrations encountered during its life in real environmental conditions one of the shock testing formats is the shock response spectrum. Under modal time analysis, i also only see a table with two points. The horizontal axis shows the natural frequency of a hypothetical single degree of freedom sdof, and the vertical axis shows the peak acceleration which this sdof would undergo as a consequence of the shock. A full shock response spectrum for the base input is given in figure 12. For the direct transient analysis to be consistent with the spectral analysis we. When the analytical half sine pulse is applied to the fem, a response acceleration transient is computed for points around the structure where components are mounted.
Cam operated bounce test for transportation evaluation of ista requirements. Functional shock test per milstd810 equivalent static load. Here are the links to the paper referenced and the blog post containing it. Use modes to a frequency of hz with 3% critical damping. The machine is fabricated with mild steel of a very robust design to provide necessary mechanical strength and rigidness. Calculation of maximaxpositivenegative shock response spectrum. If an undamped springmass system has a mass of m 10 kg and spring constant of k 2000 nmeter, determine 25 points a the maximum displacement of the mass when the system is subjected to a halif sine pulse with time duration of t 0. The report shows an important type of modal interaction failure which cannot be adequately excited with a symmetrical waveform even if testing is ac. Approximation of continuous transfer function by discrete transfer function. This option provides fast and efficient structural model generation and full 3d visualization of the online vibration pattern on the structure under test. Shock response spectrum of rectangular pulse excitation. Shock with half sine, haversine, triangular or sawtooth pulses iec 68227, milstd202 shock response spectrum srs with frequency weighted spectral density more sophisticated shock testing and vibration testing methods that may be customized for your particular product. Application for calculating the shock response spectrum in order to determine how shocks will affect a structure. Aug 24, 2006 this program calculates the shock response spectrum for a base input, where the base input is in the form of an acceleration time history.
To find the response of system they used duhamels integral method. When the analytical halfsine pulse is applied to the fem, a response acceleration transient is computed for points around the structure where components are. Jan 18, 2019 vertical spectrum left for a half sine pulse with a 50g shock load with an 11ms duration right. Transfer functions for relative velocity and displacement response. Shock response spectrum srs vibration control software. Similarly, several definitions for the shock response spectrum are. Comparing 2 shock response analyses for a computer circuit. A shock response spectrum srs is a frequency based function that is used to indicate the magnitude of vibration due to a shock or transient event. It has been observed that, as the duration of the impulse load approaches time period of the system, amplitude vibration becomes maximum. Response spectrum analysis is a method to estimate the structural response to short, nondeterministic, transient dynamic events. Shock response spectra control srs optional vr9302.
The shock response spectrum quantifies the damage potential of the shock. Tripartite plot of the response spectrum for the half sine pulse. Now this signal processing method is standardized by iso 184314 mechanical vibration and shock signal processing part 4. Functional shock test per milstd810 equivalent static load mechengdude. Examples of such events are earthquakes and shocks. Shock response spectrum srs frequency range up to 20 khz. The shock programmers for half sine shocks are usually rubber or felt. Shock response spectrum 1 10 100 0 1 10 100 0 natural frequency hz g time history. Shock response spectrum analysis for input signals. It may also be used for evaluating classical pulses, such as a halfsine pulse. Up to 8 channels for control, alarm checking on master module. Many different waveform synthesis generation techniques included. Fivepercent damped pvss on a fourcoordinate display of the g, 200 ips, half sine, droptable shock. A halfsine acceleration transient applied to a base frame structure simulating a drop shock event.
Shock and vibration test for product qualification rexnord. Import of ascii data for replication with pulse editor. Srs package adds shock response spectrum srs plots to shock and transient capture test modes. A shock response spectrum srs is a graphical representation of a shock, or any other transient acceleration input, in terms of how a single degree of freedom sdof system like a mass on a spring would respond to that input. The software system receives the acceleration data from a lower computer, then processes the data and uses fft and shock response spectrum srs to judge shock test result. Piersol12 commented on shock severity in terms of velocities, and shock severity estimation howard a. Shock response analysis will derive a shock response spectrum for a time trace. Functional shock test per milstd810 equivalent static load twoballcane mechanical 11 sep 07 14. In this step, the time data is transformed to the frequency domain. Shock response spectrum file exchange matlab central. Since the exact time history of the load is not known, it is difficult to perform a timedependent analysis.
Shock response spectrum srs in matlab mathworks, inc. The machine produces the shock pulses using compressed air to force the platform to impact on the elastomer pads half sine programmer padswhich are placed between the platform and anvil of the impact area to produce half sine pulses, lead pellets are. Response of a singledegreeoffreedom system to a simple drop shock. Acc hamer400030002000 0 0,00 0,05 0,10 0,15 0,20 time s ms2 shock response spectrum 10 100 0 1 10 100 0 00 natural frequency hz ms2 acceleration during impact of a steel hammer to the plastic shield. Evaluating the shock response results for the response spectrum analysis. This requires the system to be loaded with a halfsine shock wave at a frequency equal to the natural frequency of the system. Srs shock response spectrum can execute the test in which the test condition and evaluation are conducted not based on waveform itself, but on srs analysis. This requires the system to be loaded with a half sine shock wave at a frequency equal to the natural frequency of the system. Solidworks simulation shock response introduction duration.
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