## 1 Introduction  
Many studies have proven that composite materials have higher specific energy absorption (SEA) characteristics compared to their metallic alternatives [1]. However, a lack of understanding of their responses under various conditions and energy absorption mechanisms has hindered exploiting their full potential. Having a standard experimental way of exploring the crashworthiness of composites makes it possible to fully understand their mechanisms, define a proper mechanical material model and get the values for the material coefficients, and compare the materials with respect to their SEA. In 1989, [PERSON] investigated the energy absorption capability of composite tubes and beams and categorized four characteristic crushing modes: transverse shearing, brittle fracturing, lamina bending, and local buckling [2]. A year after, in 1990, [PERSON] studied progressive crushing of fiber-reinforcedcomposite tubes and characterized splaying and fragmentation as energy absorption mechanisms [3] which were respectively similar to lamina bending and brittle fracturing modes stated by [PERSON]. [PERSON] et al. reviewed the experimental works up until 1998 and summed up the failure modes, categorizing them into five categories: transverse shearing, brittle fracturing, lamina bending, delamination, and local buckling [4]. These researchers stated that the actual crush of a composite is a combination of these modes and the SEA differs depending on which mode is the most prominent. This emphasizes the importance of having a fixture to study different modes of crushing under diverse conditions. Since up to this date there is no standard test method to characterize the crashworthiness of composites, each researcher has chosen his or her own approach. Many have chosen self-supporting geometries like cylindrical [5; 6], square [7], or conical [8] tubes, with sinusoidal [9] or omega (\(\Omega\))-shaped [10] structures also being considered. [PERSON] [11], [PERSON] et al. [12], and other researchers compared the various energy absorption mechanisms of the same material with different geometries, dimensions, and triggering mechanisms. Their results proved that SEA is not an intrinsic property of the composites and is heavily dependent on the shape and geometry of the specimen. To avoid the complexities and expenses of the manufacturing of self-supporting specimens, some research groups have tried to perform tests on plates. Since flat specimens, when submitted to lateral compressive loads, tend to buckle, application of an anti-buckling fixture to support the plates is mandatory. One of the first fixtures of this type found in literature is mentioned in the NASA contractor report 4562 [13] developed by [PERSON] and [PERSON]. With the application of knife-edge supports, those researchers were able to abolish the problem of the binding of the load transfer platen and achieved sustained crushing loads over long strokes. However, the fixture did not permit from formation, i.e., the typical result of the progressive failure mode, and the accumulation of debris near the crush zone caused jamming of the specimen [14]. Other research groups in universities and institutes have tried to overcome these problems and have manufactured their own fixtures. Table 1 gives a comparison of some of these fixtures [14]. This again emphasizes the importance of having a fixture capable of performing standardized tests under both quasi-static and dynamic conditions with reliable and reproducible results replicating the crush modes happening in a real component. Further, the test results obtained with a standardized fixture can be used to calibrate material card parameters in numerical investigations, which can then be used to predict component level damage as was done by [18]. All these aspects were considered during the fixture design process to create a fixture with reliable and reproducible results for future standardized tests of the crashworthiness of composite plates.