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This article proposes a thermo‐elastic topology optimization with stiffness, strength, and temperature constraints involving a wide range of temperatures. The state equations for the linear elasticity and heat conduction are considered. Formulations involving minimum volume with compliance, stress and temperature limits under multiple thermal conditions are presented. The global stress and regional temperature metrics adopting the corrected aggregation function are used to evaluate the maximal stress and temperature, respectively. The stress stabilizing scheme is utilized to overcome the iteration oscillation stemming from highly nonlinear behavior of thermal stress constraints for multiple thermal conditions. To achieve clear optimized topologies under design‐dependent loads, a continuation strategy for the relaxed Heaviside function is developed. Two 2D numerical examples are employed to illustrate the validity and practicability of the proposed approach. The results show that the optimized structures designed by a certain temperature may be damaged or have thermal deformations once the ambient temperature changes due to the thermal residual stress. The designs covering wide temperature range achieved by neglecting stiffness or strength constraints can result in stiffness reduction or strength failure. It is therefore imperative for the optimization to adopt a multi‐physics model involving multi‐constraints over a wide temperature range. [ABSTRACT FROM AUTHOR]

A thermo‐elastic topology optimization with stress and temperature constraints is proposed to attack the complex multiphysics problem in this paper. Based on the rational approximation of material properties (RAMP), the coupled equations of mechanic and temperature field are solved. Two optimization problems, volume minimization with temperature and stress constraints, and traditional compliance minimization with volume and temperature constraints, are discussed for comparison. The stress stabilizing control scheme (SSCS) combined with global stress measure is presented to tackle highly nonlinear and local nature of stress with thermal expansion in varying temperature field. The adjoint method is applied to achieve the sensitivity of multiphysics field and the density function is updated utilizing the method of moving asymptotes (MMA). Representative examples are investigated to demonstrate the effectiveness and utility of the proposed method. Clear topology and stable iterative process can be obtained for complex coupled problem by means of the SSCS. Meanwhile, the topology with stress and temperature constraints has obvious sensitivity to even subtle change in temperature. The optimization design considering several stress constraints under multithermal conditions can work well in different temperature ranges. [ABSTRACT FROM AUTHOR]

Summary: Experimental methods and theoretical analysis are employed to investigate the effects of horizontal projection on upward flame spread over extruded polystyrene thermal insulation material of building façade. The average flame height (Hf) (or area S) drops exponentially as dimensionless projection width (w*) rises, and dropping rates are more significant for wider projection. The decrease of flame area is more remarkable than that of flame height. There exists a low temperature zone which is surrounded by the horizontal projection, the flame, and the façade. The average of maximum temperature ( T ¯ max) of zone below the projection first decreases and then increases as projection width (w) rises. The temperature dropping rate increases exponentially with w*. T ¯ max of the zone adjoining the surface of extruded polystyrene sample above the projection decreases linearly with w*. For wider projection (w ≥ 10 cm), the average temperature above it first increases and then drops as height rises. The heat flux history could be divided into 4 stages, ie, ignition stage, smoke heat transfer stage, flame heat transfer stage, and attenuation stage. The average heat flux ( q ̇ ″) at each stage decreases as w rises. The maximum value is observed at the third stage, where q ̇ ″ increases linearly with S. [ABSTRACT FROM AUTHOR]