Thermal stress performance of glazed units contained phase change material

The low heat transfer and high energy storage performance of phase change material (PCM) will improve the thermal performance of the PCM-glazed units. However, decreasing the heat transfer results in uneven thermal load on the surface of the PCM-glazed units, which is an important cause of thermal stress in such units, because the glass in glazed units is a fragile material, and then large thermal stress can result in cracks and possible fallout of the glazed units. To study the thermal stress distribution of PCM-glazed units, a method combined numerical simulation and experimental analysis was conducted. First, the heat transfer performance and thermal stress distribution of PCM-glazed units with PCM thicknesses between 3 and 11 mm were experimentally investigated. Results showed that the thermal performance of a glazed unit was improved by adding PCM, and the variation of thermal strain on its surface with a PCM-layer thickness of 7 mm was the smallest in five test facilities. Then, the thermal stress was numerically investigated regarding the PCM height and the aspect ratio of the PCM-glazed unit. The higher the PCM height, the greater the maximum strain. An aspect ratio of PCM-glazed units of 1.5 was recommended.

Mutual Influence of Geometric Parameters and Mechanical Properties on Thermal Stresses in Composite Laminated Plates with Rectangular Holes

In this research, the mutual influence of the mechanical properties and geometric parameters on thermal stress distribution in symmetric composite plates with a quasi-rectangular hole subjected to uniform heat flux is examined analytically using the complex variable technique. The analytical solution is obtained based on the thermo-elastic theory and the Lekhnitskii’s method. Furthermore, by employing a suitable mapping function, the solution of symmetric laminates containing a circular hole is extended to the quasi-rectangular hole. The effect of important parameters including the stacking sequence of laminates, the angular position, the bluntness, and the aspect ratio of the hole and the flux angle in the stacking sequence of [45/−45]s for composite materials are examined in relation to the thermal stress distribution. The thermal insulated state and Neumann boundary conditions at the hole edge are taken into account. It is found out that the hole rotation angles and heat flux angle play key roles in obtaining the optimum thermal stress distribution around the hole. The present analytical method can well investigate the interaction of effective parameters on symmetric multilayer composites under heat flux.

Investigation of Elastic Tensile Behavior of Thermoplastic Discs Reinforced With Steel Wires

In this study, the stresses occurring in the thermoplastic composite disc were investigated by numerical analysis. Assuming that the modulus of elasticity does not change with temperature, temperature distributions of 20 oC, 40 oC, 60 oC, 80 oC, 100 oC were taken as reference in the study. Composite materials are created by combining the best properties of two or more materials or by creating a new property. Thermoplastic composites, on the other hand, are bendable and ductile. It is vital to know the thermal behavior of these materials, which are preferred in many areas of technology. At the end of the numerical analysis, the radial and tangential stress values calculated at high temperatures; It has been observed that it is greater than the radial and tangential stresses calculated at low temperatures. It has been observed that the tangential stresses are greater than the radial stresses. It was concluded that the increase in the value of the temperature acting on the thermoplastic disc directly affects the thermal stress distribution and values.