Toshio Tanimoto

Progressive Nature of Fatigue Damage of Glass Fiber Reinforced Plastics

The progressive nature of fatigue damage due to cyclic loading on glass fiber reinforced plastics was studied. The residual strength of the specimens subjected to fluctuating tension with a given number of cycles was measured, and the number of cracks developed in the samples were counted by means of a microscope. From our test results, the progression process of fatigue damage in the composite materials can be divided into three stages.

RESIDUAL STRENGTH DEGRADATION MODEL FOR GLASS/POLYESTER LAMINATES UNDER REPEATED TENSION AND COMPRESSION LOADINGS

ABSTRACT Experimental studies were first performed on the residual strength degradation process of Glass/Polyester laminates under repeated tension and compression. Then, a new residual strength degradation model was devised for this material and the validity of the proposed model was examined through the comparisons with the sufficient amount of test data. It is of great interest to note that the statistical distribution of fatigue life has been derived, from the proposed model, to be a well-known double exponential distribution. It is also shown that the model can be easily extended to reflect the engineering reality for other kinds of composite and different loading conditions.

RELIABILITY-BASED FATIGUE-PROOF DESIGN OF COMPOSITE MATERIALS

ABSTRACT The reliability-based design safe lives of composite materials have been investigated through the statistical modelling of the failure probability under service loads from the viewpoint that the failure probability has to be evaluated only through the limited number of experimental data which would, of course, vary from sample to sample.

FATIGUE LIFE DISTRIBUTION ANALYSIS OF GFRP IN CONSIDERATION OF SPATIALLY DISTRIBUTED RANDOM CRACK PROPAGATION RESISTANCE

ABSTRACT The present paper deals with fatigue life distribution analysis of GFRP in consideration of spatially distributed random propagation resistance utilizing the Tsurui-Ishikawas stochastic crack growth model. At least 20 replication tests under constant stress amplitude are first performed at each stress level of four different levels to empirically characterize the scatter in the number of cycles to failure. Then, the effect of random crack propagation resistance in GFRP on the crack propagation life distribution is clarified, and the statistical properties of the fatigue crack process for GFRP material is also investigated. Finally, discussions are made on the pertinent method for the quantitative prediction of fatigue life of GFRP, which becomes undoubtedly of vital importance in the reliability-based design and the reliable utilization of this material.