1.Science and Technology on Advanced Functional Composites Laboratory， Aerospace Research Institute of Materials & Processing Technology，Beijing 100076;2.The First Military Representative Office of the Rocket Army Equipment Department， Beijing 100190
Characterizing the axial compressive properties is always the difficulty in the fields of investigating the mechanical performance of the composite materials. In this paper， the pros and cons of four test methods for determining the compressive properties of the composite materials are comparatively summarized， by experimental investigations， mechanism analysis and computational simulations， based on domestic T800-grade composites and M40J-grade composite. Additionally， the optimized test conditions are proposed. The results of experiments and simulations indicate that the compressive strength determined by the test method of GB/T 3856—2005 is decreased by 9% than that of the test method of ASTM D3410—2016， due to premature failure， although the compressive force is both introduced through shear for the two methods. Whereas， the compressive strength measured by the end-loaded method of SACMA SRM 1R-94 is 3% to 6% higher than that of the method of ASTM D3410—2016 and D6641—2014. Moreover， the experiments for optimizing the test conditions demonstrate that the strengthening tabs have a noticeable effect on the measured compressive properties for the high-performance carbon fiber composites. Accordingly， tabs made of metal are suitable for composite materials with strong interfacial bonding and high fracture strength； while tabs made of glass fiber reinforced polymer are suitable for those with weak interfacial bonding and low fracture strength. From the images of the fracture appearance of the specimens， it is observed that there are typical failure modes of ‘kinking band’ of the fibers for both the shear-loaded method and the end-loaded method. Therefore， the end-loaded compression method is a preferable method for determining the compressive strength of the composite materials， considering the measured results and failure modes.