Abstract:
The compressive strength, internal failure mechanisms, and comparison of failure stress
state of 2D fiber reinforced woven composites and 3D fiber reinforced angle-interlocked woven
composite is investigated through experimental work, SEM, finite element analysis and failure
theories. The aim for this research work is to check the feasibility of ASTM D6641 (which
compression through combine end and shear loading method) for 3D fiber reinforced woven
composites. A 3D finite element model is developed in ABAQUS based on homogeneous
orthotropic laminate to investigate the stress variation and failure stress state in the gage section
of the specimen. Two different failure theories in three dimensions are considered i.e. fully
interactive three dimensional Tasi Wu failure criteria and limit criteria i.e. Maximum stress used
for failure prediction. The broader aim of this research work is the development of testing
standard for mechanical testing of 3D fiber reinforced woven composites.
Through experimental work and finite element analysis it is found that compressive
properties of 3D fiber reinforced woven composite is lower than the 2D fiber reinforced
composite materials. SEM investigation is carried out to study the internal failure mechanisms in
specimens. In 2D fiber reinforced composites the major cause of failure is fiber micro-buckling,
fiber breaking and kink band formation, where as in 3D fiber reinforced composites the major
cause of failure is fiber breaking and kinking at various locations. Finite element analysis shows
that major compressive stresses are developed in the gage section and stress distribution is
uniform. ASTM D6641 is used for compression testing of 2D fiber reinforced woven
composites, when ASTM D6641 is used for compression testing of 3D fiber reinforced woven
composites results shows higher standard deviation and coefficient of variance. Based on
Experimental work and SEM investigation we can use ASTM D6641 for testing 3D fiber
reinforced woven composites.
