Volume 1, Issue 10 (November 2004)
Variations in the Mechanical Strength of a Composite Material of Thermoplastic Matrix Reinforced with Woven Glass-Fabric After Being Submitted to Diverse Damage Sequences: A Statistical Analysis
The aim of the present study is to characterize statistically the degradation produced in the tensile breaking strength of a material composed of a PEI thermoplastic matrix reinforced with woven glass fiber under a sequential permutation of damage. To do so, the statistical theory of extreme values was applied to the experimental results, which enabled us to calculate the probability of failure of the material. The simulated damage corresponding to said series was the following: fatigue up to one million cycles at a maximum stress of 20% of the tensile strength, impact damage with an energy of 5.07 J, accelerated aging under conditions of 95% relative humidity, a temperature of 70°C for a period of 360 h, and finally, thermal aging at 150°C for 360 h. The experimental results obtained show losses in residual strength of between 20 and 35% of that presented by the material in its original state.