Probabilistic structural analysis of a composite beam considering random field of interface

Abstract

The interlayer component is the weak layer of the composite beam. For the post-strengthened beam, the upper and lower layers are connected by glue bonding. The glue is mainly applied manually, and the craft has great randomness, and the randomness has spatial variability, which affect the normal use and bearing capacity reliability of the composite beams. In order to study the probability response of composite beams considering the spatial random field characteristics of interlayer materials, a finite element model was established. The upper and lower beams were both Euler beam, and the interlayer components were regarded as continuous springs, which were discretized and used as springs to connect the upper and lower beams into system stiffness. The random field characteristics of the continuous spring were expressed by Karhunen-Loéve expansion, and the statistical moments of the response were calculated by the reduced-dimension point estimation method, forming the calculation strategy of KLE-PEM. The comparison with MCS shows that this strategy has high accuracy and efficiency. Probabilistic structural response of composite beams with different correlation length, coefficient of variation of interface stiffness and interface stiffness of were analysis. The results show that the correlation length has little effect on the probability distribution of the response compared with the interlayer stiffness and its coefficient of variation (COV). The COV of interlayer stiffness has little influence on the mean value of the response but has great influence on the dispersion of the result. The greater the COV is, the greater the dispersion of the result is. The interlayer stiffness has a great influence on the statistical characteristics of the response, and within a certain range, the greater the interlayer stiffness, the smaller the deformation of the composite beam and the smaller the probability range.