No abstract

Composite materials have been manufactured using bidirectional jute yarn in a polyester matrix. The manufactured composite has been subjected to water aging for various times of immersion (90, 180, and 270 days). A significant decrease of fatigue strength has been observed during water aging. The number of cycles to failure of the aged and nonaged specimens were correlated using the two-parameter Weibull distribution function to determine the probability of failure and plot the S-N curves at different reliability levels. The results have shown that the two-parameter Weibull distribution describes the fatigue life probability distributions of jute-reinforced polyester composite material with highly significant statistical correlation coefficients.

No abstract

No abstract

This paper deals with the stability and the dynamics of a harmonically excited elastic perfectly plastic asymmetrical oscillator. The hysteretical system is written as a nonsmooth, forced autonomous system. The dimension of the phase space can be reduced using adapted variables. It is shown that asymmetry of boundary conditions (forcing term) and material asymmetry lead to an equivalent system for this simple structural case. The forced vibration of such an oscillator is treated by a numerical approach by using time locating techniques. Stability of the limit cycles is analytically investigated with a perturbation approach. The boundary between elastoplastic shakedown and dynamic ratcheting is given in closed form. It is shown that the divergence rate is strongly correlated to the internal asymmetry of the oscillator.