Shock Testing Services


Our shock testing engineers will condition, plot and help you analyze up to 128 channels of real time data - Shock Response Spectrum (SRS), Fast Fourier Transform (FFT) or modal analysis.



Classical Shock Test


Classical Shock Testing

Classical Shock Testing is accomplished using many facilities here at DTB. The typical shock testing event can be performed on our Unholtz-Dickie T-4000 and T-1000 vibration testing systems. These Vibration Testing systems coupled with 360KVA of amplifier power permits the system to achieve shock testing levels of over 100Gs. Also, ask about our new T5500 with head expander, integrated slip table and 3 inch displacement.


For tests that required higher levels or longer duration, DTB has additional mechanical shock testing machines. Using these shock testing facilities, levels of 3000 G and 4 mSec, half sine shocks have been developed for our customers. Longer duration shock testing pulses have also been obtained. These long duration pulses range from over 1 second in duration using our Catapult facility to 100 mSec.


Modern engineering techniques often call for unusual and difficult shock testing and vibration testing requirements. However, DTB's staff of highly skilled engineers and technicians have years of experience in setting up and running these types of dynamic tests.



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Pyrotechnic Shock Test


Pyrotechnic Shock Testing

Our Shock Testing group has developed and refined the ringing plate method of producing repeatable Shock Response Spectrums (SRS) to over 32,000 Gs. Our pyrotechnic shock testing facilities and mechanical shock testing machines (small and medium weight) can be tailored to produce the required shock pulse.


These shock testing facilities can produce this high level as well as lower level ringing out to 10,000 Hz.


The knee of the SRS can be adjusted from 1000Hz to 2000Hz to meet the demands of your pyrotechnic shock test requirements.


In our lab, the test item size is NEVER an Issue. Items as small as an integrated circuit to as large as 3400 kgs (7,500 lbs), are subjected to various shock testing methods, such as the shaking profile of a truck on a potholed road, the shock of a torpedo hitting a submarine or the controlled explosions on a spacecraft.



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Hammer Shock Testing


DTB has Medium weight hammer shock as well as light weight hammer shock testing facilities, which are both Navy Certified and approved.


These shock testing facilities are totally capable of performing Mil-S-901 test requirements.




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Dynamic Design Analysis Method for Shock Design


DDAM stands for Dynamic Design Analysis Method which is a U.S. Navy standard procedure for shock design. Shipboard equipment must satisfy stringent maritime and naval requirements for durability, shock resistance, and functionality.


Typically DDAM method is used to analyze the shock response at the mountings of shipboard equipment, like masts, rudders, propulsion shafts etc, due to underwater explosions. All mission-essential equipment on board surface ships and submarines must be qualified for shock loads, such as from depth charges, mines, missiles, and torpedoes.


Traditional DDAM analysis is a manual procedure in which results from frequency response analysis are post processed to provide an estimate of shock resistance. But with current finite element analysis simulation software the analysis can also be performed using commercially available FEA codes.


DDAM simulates the interaction between the shock-loaded component and its fixed structure. DDAM takes this effect into account in relation to the weight of the equipment, mounting location and orientation of the equipment on the vessel.


ANSYS provides an efficient means to perform DDAM simulation through an intuitive, interactive user interface, automatically generating the associated reports as specialized output data and tables. After performing a natural frequency analysis to determine the mode shapes and natural frequencies, a DDAM analysis is performed using an input spectrum of displacements or accelerations.


The input spectrum values are provided automatically by the software, based on data from unclassified U.S. Navy documents (primarily Naval Research Laboratory Report NRL-1396). Optionally, you can provide user-defined coefficients, which can be for an alternate unit system, or classified coefficients. The security of classified coefficients is maintained through the ability to run the DDAM portion of the analysis on a secured computer.


The DDAM analysis processor uses the Naval Research Laboratory (NRL) summation method to combine the peak responses from all mode shapes into overall displacements and stresses. Results can be viewed for each mode shape and the resultant in the Results environment



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