Prediction of concrete performance at high temperatures is of great importance, in particular for safety evaluation of concrete structures in fires in tunnels and high buildings or in thermal hazard situations like hypothetical core disruptive nuclear accidents. High temperatures induce strong physical and chemical changes in the micro-structure of concrete that affect its mechanical behaviour....

In this paper we report on the mechanism of delamination in light-emitting diode (LED) packages and its effects on thermal characteristics of LEDs. The LED samples were subjected to moisture preconditioning treatments followed by heat block testing. Transient thermal measurements were performed for the investigation of the thermal behavior of the delaminated LEDs. Increase of thermal resistance...

In this article, the problem of time-dependent stress redistribution of a piezomagnetic rotating thick-walled cylinder under an axisymmetric hygro-thermo-magneto-electro-mechanical loading is analyzed analytically for the condition of plane strain. Using the constitutive equations, a differential equation is found in which there are creep strains. Primarily, eliminating creep strains, an analyt...

A coupled elastoplastic-damage constitutive model taking into account chemo-induced elastoplastic-damage effects for the modeling of coupled chemothermo-hygro-mechanical behavior of concretes at high temperature is proposed in this article. A three-step operator split algorithm for the integration of the rate coupled constitutive equations is developed. Consistent tangent modulus matrices for c...

Damage in oak wood museum objects under indoor climate variations (relative humidity, temperature) is studied using a thermo-hygro-mechanical model. The model incorporates the effects of moisture sorption hysteresis and discrete cracking, implemented within finite element framework staggered update procedure. Sorption experiments were performed order to calibrate basic features coupled formulat...

concrete deformation due to temperature and moisture condition will always develop simultaneously and interactively. the environmentally (hygral and thermally) induced stress and deformation are essential to concrete durability. to simulate the deformation of concrete caused by the coupling effect of temperature and moisture, a numerical simulation approach is proposed comprising analytical pro...

Semi-structural bonded joints of steel components are exposed to long-term stresses in addition water diffusion, temperature changes and varying external forces during operation. These hygro-thermomechanical loadings lead successive degradation stiffness strength due damage resulting from chemical aging fatigue processes, causing failure the joint when its service life is reached. In following ...

Raw earth is emerging as a viable building material with lower carbon emissions than conventional concrete and fired bricks. an excellent passive hygro-thermal regulator, which improves occupants’ comfort while reducing the need for active heating/cooling installations. The coupled response of materials investigated by exploiting principles thermodynamics porous media unsaturated soil mechanics...

Interfacial delamination is the major reliability issue of Quad Flat No-lead (QFN) packages under the JEDEC-MSL preconditioning and reflow process. Failures will occur when the hygrothermal stress exceeds the interfacial strength. Simulation based on finite element model is a popular method for studying the failure mechanism. However, the non-accurate material properties and lack of experiment ...