Thermal stress analysis of disc brake using analytical and numerical methods

This article presents study of the thermal stress development in brake disc and the associated life cycle of the disc. The thermal stress analysis of disc brake under the first brake application and the influences of thermal loads on stress development of the disc have been investigated. The temperature distribution was conducted as a function of disc thickness and braking time. The study was done on the disc brake of Sports Utility Vehicle with a model of DD6470C. Partial solution approach was used to solve analytical temperature distribution through the thickness. The model was done using representative areas of the disc exposed to high temperature whose distribution result was obtained as a function of disc thickness and braking time. The solutions of coupled thermal transient fields and stress fields were obtained based on thermal-structural coupled analysis. Based on the model developed for the study, the positions of high and low stress formations were investigated, and it has been observed that thermal stress and temperature gradient show similar behavior through the thickness of disc. Generally, high temperature and stress components were found on the rubbing surfaces of the disc.

Study on the fire resistance of concrete-filled steel tubular column to composite beam joints after earthquake damage

Background: Post-earthquake fire is one of the secondary disasters caused by the earthquake; many earthquakes around the world have brought about severe fires and led to enormous losses. It is of great significance to study the fire resistance of structures after earthquake to improve the level of urban disaster prevention and reduce the fire loss. Methods: A nonlinear finite element model of composite joints subjected to post-earthquake fires is established based on ABAQUS software. The state after the earthquake damage is imported into the thermal-stress analysis model through the restart request in ABAQUS, and considered as the initial state of the thermal-stress analysis model. Results: It is noticed that when the damage index is less than 0.517, the damage level shows significant effect on the fire resistance, but the influence is no longer significant when the damage index reaches 0.781. When only the column is exposed to fire, the column showed obvious local buckling and overall bending deformation. Meanwhile, when the joint area below the concrete slab is exposed to fire, the joint shows a mixed failure mode of the excessive vertical displacement of beam end and column instability. Conclusion: The fire resistance of the composite joint decreases gradually with the increase of seismic damage level. The fire condition has a significant effect on the fire resistance of the composite joints; with the increase of fire area, the fire resistance of composite joints with same damage degrees decreases gradually.