Shock Testing

Hammer Shock Testing

Hammer shock testing is performed on shipboard machinery, equipment, systems, and structures. The purpose of the hammer shock test is to verify the ability of shipboard installations to withstand shock loading, which may be incurred during wartime service, due to the effects of nuclear or conventional weapons.

Here at DTB, we have lightweight and medium weight hammer shock testing facilities. For lightweight testing, we can accommodate a total of 550 lbs., including all fixturing. For medium weight testing, we can accommodate a total of 7,400 lbs., including all fixturing, as well.

Pyrotechnic Shock Testing

Our shock testing group has developed and refined the ringing plate method of producing repeatable SRSs to over 32,000 G. Our pyrotechnic shock testing facilities and mechanical shock testing machines (lightweight and medium weight) can be tailored to produce nearly any required shock pulse for your product.

The knee of the SRS can be adjusted from 1,000 Hz-2,000 Hz, and these facilities can produce lower level ringing out to 10,000 Hz, as well.

Test item size is never an issue in our lab. Items as small or large as integrated circuits or 3,400 kg (7,400 lbs.) are subject 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.

Dynamic Design Analysis Method (DDAM)

DDAM is a US Navy standard procedure for shock design. Shipboard equipment must satisfy stringent maritime and naval requirements for durability, shock resistance, and functionality. Typically, the DDAM method is used to analyze shock response at the mountings of shipboard equipment, such as masts, rudders, and propulsion shafts, due to underwater explosions. All mission-essential equipment on surface ships and submarines must be qualified for shock loads from incidents, such as depth charges, mines, missiles, and torpedoes.

The traditional DDAM method is a manual procedure in which results from frequency response analysis are post-processed to provide an estimate of shock resistance. With current finite element analysis (FEA) 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, taking into account its relation to the weight of the equipment, mounting location, and orientation of the equipment on the vessel.

ANSYS provides an efficient means by which to perform DDAM simulation through an intuitive, interactive user interface, which automatically generates the associated reports as specialized output data and tables.

After performing a natural frequency analysis to determine the mode shapes and natural frequencies, DDAM is performed using an input spectrum of displacements or accelerations. The input spectrum values are provided automatically by the software. Optionally, you can provide user-defined coefficients, which can be used for an alternate unit system.

The DDAM 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.

DTB provides military testing services for elctronic requirements.