A multi-axial spine testing system includes a physiological motion unit (PMU); a uni-axial test frame having an input; and a fixture configured to be attached to the test frame and facilitates a plurality of primary motions of one or more of the PMU and the fixture. The plurality of primary motions includes a linear motion of the input and a rotational movement of an output. The fixture has an upper assembly directly or indirectly coupled to the input. The upper assembly transfers the linear motion (T.sub.z) of the actuator to the rotational movement (R.sub.x) of the output. The upper assembly and lower assembly apply a bending moment (M.sub.X) and an axial compression (F.sub.z) to the PMU. An external transducer collects data related to or generated by at least the plurality of primary motions. The fixture simultaneously provides the bending motion and axial compression to the PMU.

Fatigue limit testing method for specimens comprising subjecting a specimen (10) to be tested to successive test blocks (1, 2, 3, 4, 5, 6, 7), each test block (1, 2, 3, 4, 5, 6, 7) comprising applying to the specimen successive cyclic loads according to load parameters with an amplitude bigger than the load parameters of cyclic loads of the preceding test block; subjecting said specimen to successive deformation tests (a, b, c, d, e, f), each deformation test being performed between two successive test blocks and comprising the application of a isolated specific load to the specimen and performing deformation measurements from said element while being subjected to said specific load; and characterizing a fatigue behavior of the specimen considering at least a variation occurring on the successive deformation measurements and considering the load parameters of cyclic loads preceding each deformation measurement.

The disclosure relates to apparatus and methods for uniaxial testing of a solid specimen, such as an asphalt or asphalt concrete specimen. The apparatus provides a simplified and accelerated procedure for mounting and testing asphalt mixture samples and other solid specimens under uniaxial tension and/or compression, in particular to measure corresponding uniaxial strain and/or fatigue in the specimen. The apparatus incorporates two opposing collet-chuck elements to rapidly mount and fixedly hold a solid specimen in place in a loading system to apply uniaxial loads. The disclosure further relates to an off-specimen means for measuring strain in a specimen using optical imaging in which successive time series images of a specimen during uniaxial loading can be analyzed to determine displacements and corresponding strains.

A repetitive impact system is disclosed for testing soft material samples under controlled impact conditions. The system includes a drop tower with a moveable mass that is repeatedly lifted and dropped by a motor-driven rack and pinion mechanism. The pinion gear may be configured to fail before other components. A sample holder is positioned in the path of the mass and may contain foam and rubber layers on one or both surfaces. An accelerometer may detect horizontal acceleration exceeding a threshold, triggering a camera to capture images for cavitation analysis. The system may apply smooth acceleration trajectories and allow adjustment of impact height based on gear tooth configuration. A method is also disclosed for detecting initial cavitation nucleation by monitoring acceleration values during repeated impacts. This system enables precise, repeatable testing of soft materials and supports real-time detection of cavitation events.