Abstract: A collision test apparatus having input and output members formed from incompressible liquids and between which is positioned a sample whose impact characteristics are to be measured. A compression wave is input to the input member and propagated through the sample and in the output member. Suitable detectors detect the input compression wave, output compression wave and any pan of the input compression wave reflected off the sample.

Abstract: The invention provides an instrument suitable for measuring seismic waves in an environment which comprises a wave guide through which a seismic wave may propagate substantially without dispersion wherein the wave guide is provided with means for measuring its deformation.

Abstract: A collision test apparatus (20) comprises input (22) and output members (23) formed from incompressible liquids and between which is positioned a sample (24) whose impact characteristics are to be measured. A compression wave is input to the input member (22) and propagated through the sample (24) and into the output member (23). Suitable detectors (33, 34) detect the input compression wave, output compression wave and any part of the input compression wave reflected off the sample (24).

Abstract: The invention provides an instrument (1) suitable for measuring seismic waves (7) in an environment (2) which comprises a wave guide (3, 4 and 5) through which a seismic wave may propagate substantially without dispersion wherein the wave guide is provided with means for measuring its deformation (6a, 6b, 6c and/or 6d).

Abstract: A vehicle shows a vehicle bumper (9) having a first member (10) and a second member (11) connected to a vehicle. Low viscosity liquid (12) is trapped in between members (10 and 11) and on impact of member (10) with an obstacle a frangible membrane (13) can burst causing a high velocity liquid jet to be expelled through channel (11a) thus dissipating the impact energy.

Abstract: Stress wave measuring apparatus includes a Hopkinson bar or pressure bar bundle system comprising an input bar bundle having input bars, and an output bar bundle having output bars 104a. A brittle test specimen is positioned in between the input and output bar bundles. Means is provided to induce a one dimensional compression force into the bar bundles. Instrumentation is introduced onto the input and output bars for measuring values of shear wave or crack propagation. The specimen may be placed under different stress conditions measured by appropriate instrumentation on the bar bundles. In one embodiment, a rod gauge is glued to a rock massive and arranged to measure wave effects generated in the rock massive. Other arrangements provide amplification of the wave effects prior to measurement by instrumentation on the gauge 500.

Abstract: A compression wave or pulse generation apparatus and method are capable of generating a compression wave or pulse in a vehicle or large structure under test, and include an impactor bar or member held during use adjacent one end of the vehicle or large structure under test and supported to resist movement in a direction away from the large vehicle or structure. The impactor bar is preloaded in the direction away from the vehicle by a hydraulic or pneumatic actuator. In use, the preload force can be quelled suddenly, for example, by triggering an explosive bolt in the impactor bar, so that the impactor bar is released into impact or energy transfer with the vehicle or large structure under test to transmit a compression wave or pulse through the vehicle or structure. Energy flow transducers in the form of elongated bar members are selectively arranged to measure the mechanical energy propagated along the vehicle or structure subjected to the stress wave under simulated crash conditions.

Abstract: Real scale investigations can be carried out on vehicle impacts using a vehicle, or part hereof, or crash barrier, tested on a large dynamic testing facility (LDTF). The LDTF includes nodes connected at either end of a sample under test crash barrier. The forces in the bar are measured by Hopkinson output bars connected at right angles at each node to measure perpendicular components of a force in the barrier. Vehicle may be equipped with additional instrumentation and used as an impactor against the barrier.

Abstract: Split Hopkinson pressure bar apparatus capable of generating a compression wave or pulse in an input bar or member, said apparatus comprising an input bar or member, actuator means, a fragile or frangible component and an impactor bar or member held, in use, adjacent one end of the input bar or member and supported to resist movement in a direction away from said input bar/member when the impactor bar/member is pre-loaded in said direction by actuator means, the apparatus being such that, in use, the pre-load force can be quelled suddenly so that the impactor bar/member is released into impact or energy transfer with the input bar/member thereby transmitting a compression wave or pulse through the input bar to a specimen under test.