Optimization of a Test Bench for Testing Compliant Elements Under Shear-Force-Free Bending Load

As a contribution to the efficient cyclic testing of textile-reinforced compliant structures, a kinematic test rig for the static and dynamic bending test of composite stripe specimens has been developed [1]. This multifunctional six-membered linkage allows a moment application free of shear force by providing a pure bending load while bending the specimen in one direction up to 90°. During cyclic testing with a frequency of 1 or 2 Hz the progressive damage behaviour meaning the initiation and propagation of fibre breaks with increasing load cycles up to complete structural failure has been monitored using industrial computer tomography [2]. The test results showed considerable differences within the results and therefore led to a need for a modified test rig to reach higher frequencies. Hence, a new concept for a shear-force-free bending test bench has been developed which allows a periodic bending in both directions from 90° up to 90°. This paper intends to make contributions to the efficient cyclic testing of textile-reinforced compliant structures by optimizing this new mechanism structure to minimize the induced shear force.