Residual stress and failure analyses of polymer matrix composites considering thermal cycling and temperature effects based on classical laminate plate theory

The effects of temperature and thermal cycling on the residual stress and failure behavior of different polymer matrix composites have been investigated in this paper. A new algorithm within the framework of the classical laminate plate theory (CLPT) has been presented to calculate the residual stresses. The modified Tsai-Wu failure criterion has been employed to study the failure behavior of different stacking sequences. Numerical results show that the residual stress and failure index of the composites decrease with the increase of the temperature. It has also been established that thermal cycling condition leads to reduction of the residual stresses and increment of the failure index.

Composite riser reliability under harsh environmental conditions

Offshore engineers are looking to explore resources further from shore and at greater depths. A number of papers have indicated that composite materials may provide benefits at these depths. However, there are only a small number of risers in-service and with no history of operation these applications require experiments and theoretical investigations to ensure the safety and increase the knowledge about how they will survive the deep-water conditions. This paper therefore investigates a simplified model for composite risers for application to reliability analysis. A static catenary model is used with classical laminate plate theory used to generate stresses in the composite. This is connected to a Monte Carlo Simulation which is used to compare composite risers in harsh and normal conditions.

Fatigue Characterization of Piezo-Active Beams in Bending

This paper presents the fatigue characterization of piezo-active beams in bending with surface bonded Macro-Fiber Composite actuators. Three substrate materials are considered: stainless steel, aluminum, and brass. First, the bending response is quantified theoretically using the classical laminate plate theory. The theoretical bending results indicate that the beam with the steel substrate had the largest curvature, and the specimen with the aluminum had the least. Next, midpoint deflection in a simply supported configuration in response to harmonic quasi-static actuation is experimentally measured. The results from the experiments showed no evidence of degradation of actuation for up to four million cycles at the harmonic excitation amplitude of 500 V; however, the results appeared highly sensitive to temperature.