ON THE DECREASING FLEXURAL MODULUS OF GLASS/VINYLESTER COMPOSITE BEAMS UP TO FAILURE STATE

Abstract

COMPARISON OF THE FAILURE STATE FOR COMPOSITE LAMINATES UNDER BEND-ING AND TENSILE LOADS IS A WELL-KNOWN ISSUE WHICH IS DISCUSSED IN THE LITERATURE INTENSIVELY. THE SCOPE OF THIS PAPER IS INVESTIGATED BY THE AID OF EXPERIMENTAL AND NUMERICAL PROGRAMS. THE NUMERICAL STUDY IS PERFORMED THROUGH PROGRESSIVE DAMAGE ANALYSIS (PDA) APPROACH. THE OBTAINED RESULTS FROM PDA ARE VERIFIED BY THE EXPERIMENTAL RESULTS FOR THE TENSILE SPECIMENS. THEN THE PROCEDURE IS USED TO PREDICT FAILURE OF THE BEAM SPECIMENS UNDER THREE-POINT-BENDING (3PB) CONDITIONS. BOTH INTER-LAMINAR AND INTRA-LAMINAR DAMAGES ARE INCLUDED IN THE DEVELOPED MODELS. THE FIRST TYPE OF DAMAGE IS EXAM-INED BASED ON THE CONTINUUM DAMAGE MECHANICS (CDM) APPROACH AND THE SECOND ONE BASED ON THE VIRTUAL CRACK CLOSURE TECHNIQUE (VCCT). THE BOUNDARY CONDITIONS FOR THE BEAMS ARE SIMULATED ACCU-RATELY IN THE ANALYSES. THE FLEXURAL MODULUS AND STRENGTH OF THE BEAMS WITH VARIOUS LAYUPS ARE ESTIMATED TO BE COMPARED WITH THE TENSILE BEHAVIOR OF LAMINATES. THE STRAIN-BASED FAILURE CRITERION COULD PREDICT FAILURE OF THE COMPOSITE BEAMS IN CONSISTENCY WITH THE ULTIMATE STRAINS MEASURED FOR THE TENSILE SPECIMENS.