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Effects of moisture and temperature on the behaviour of composite T‐joints made of carbon fibre composite (CFC) materials are investigated. T‐joints may be exposed to moisture and temperature during their service life. Under such circumstances moisture and temperature diffuse into T‐joints. As a consequence, the stiffness and strength properties of the laminates are degraded. Moreover, since the laminae in the laminate cannot deform freely, residual stresses are introduced. The analysis is carried out by the finite element method using a modified thick shell element that takes into account the hygrothermal effects. The analysis also accounts for the lamina material properties at elevated moisture concentration and temperature. Deflections are presented in the form of contours, and maximum stresses developed in the Redux layer are presented in tabular forms. Two stacking sequences with clamped boundary conditions are considered for each variation in moisture and temperature

By using the central limit theorem, it is possible to consider the Fourier’s transform of a stochastic process with independent increments as a Gaussian random variable of which the mathematical expectation and the variance are respectively integrals of the mean and the variance of this process. One can then use this result to analyze the statistical properties of linear feedback systems in the frequency domain, that is to say in terms of transfer functions. The advantage of this approach is that one can deal with linear systems subject to squared white noises, in a very simple manner.