Papers by Keyword: Moving Heat Source

Abstract: This paper deals with a mathematical model of thermoelastic rectangular nano-beam, which is thermally loaded by thermal shock and subjected to moving heat source with constant speed. The nano-beam has been clamped-clamped and its length along the x-axis. The governing equations have been written by using the Euler–Bernoulli equation of nano-beams and the non-Fourier heat conduction with one-relaxation time. Laplace transform has been applied with respect to the time variable, and the solutions have been derived in its domain. The numerical solutions for the Silicon material have been done by using Tzou method. The results have been shown in figures for the temperature increment and the lateral deflection with various values of heat source speed to stand on its effects. Moreover, the effects of the ratio between the length and the width of the beam have been discussed. The speed of the heat source and the dimensions of the beam have significant effects on the temperature increment and the lateral deflection of the beam.

Abstract: The quality of joining has assumed a greater role in fabrication of metal in recent years, because of the development of new alloys with tremendously increased strength and toughness. Submerged arc welding is a high heat input fusion welding process in which weld is produced by moving localized heat source along the joint. The weld quality in turn affected by thermal cycle that the weldment experiences during the welding. In the present study a simple comprehensive mathematical model has been developed using a moving heat source and analyzing the temperature on one section and then the temperature distribution of other section are correlated with time delay with reference analyzed section.

Abstract: In high speed machining, temperature distribution in workpiece is the main factor which directly affects the surface integrity and dimensional accuracy of machined workpiece. In this paper, the machined workpiece temperature in high speed peripheral milling is analyzed through using moving heat source method and inverse method. Firstly, the workpiece to be machined is considered as a semi-infinite solid to model the transient surface temperature using arc-shaped moving heat source. Inverse method is then applied for the calculating of heat flux. Peripheral milling experiments of 1045 steel is performed with coated carbide insert The machined surface temperatures were measured during experiments. The measured results were found to be in agreement with the predicted ones by transient models for machined surface temperatures. These results confirm the conclusion that the transient workpiece temperature will decline when the cutting speed increases to a critical value.

Abstract: nternal heating of hollow cylinders with moving periodic heat source is examined in relation to surface treatment applications. This study includes three different cylinder materials, namely aluminum, nickel and titanium. Effective stresses in the cylinder wall are found to be mainly attributed to longitudinal temperature gradients. The aluminum cylinder shows sharper longitudinal temperature gradients as compared to the nickel and the titanium cylinders, which is due to the high value of the aluminum specific heat capacity. However, the larger Eα (elasticity modulus × thermal expansion coefficient) values for nickel cylinder result in higher levels of stress although nickel and titanium cylinders exhibit similar longitudinal temperature profiles. During dwelling time for the heating source at a certain spot, titanium cylinder exhibits lower levels of temperature increase as compared to aluminum and nickel cylinders, due to its lower value of thermal conductivity.

Abstract: A finite element heat transfer model incorporating a moving heat source has been developed to predict the temperature field in traverse cylindrical grinding. The model was then applied to analyse the grinding-hardening of quenchable steel 1045. It was found that in the region where the grinding wheel had an entire contact with the workpiece, material would experience a heating-cooling cycle, enabling the generation of a uniform hardened layer. In the transient regions at the two ends of the workpiece where the wheel-workpiece contacts were partial, the material was not hardened but experienced an annealing process. The results were in good agreement with the experimental observations.

Abstract: A three-dimensional finite element heat transfer model incorporating a moving heat source was developed to investigate the heat transfer mechanism in grinding-hardening of a cylindrical component. The model was applied to analyze the grinding-hardening of quenchable steel 1045 by two grinding methods, traverse and plunge grinding. It was found that the heat generated can promote the martensitic phase transformation in the ground workpiece. As a result, a hardened layer with a uniform thickness can be produced by traverse grinding. However, the layer thickness generated by plunge grinding varies circumferentially. The results are in good agreement with the experimental observations.

Abstract: In this paper, an analytical model is developed for prediction of temperature rise on workpiece surface during machining and orthogonal cutting is studied. The shear heat source created in the primary zone and the friction heat source on the tool-workpiece interface determine the workpiece temperature. The proposed model is verified with FEM simulation and experimental measurements of temperature on AISI4340 in the literature. With the analytical model presented here, substantial reduction in computational time is achieved in the predictions of machining workpiece temperature rise.

Abstract: When the coal (rock) specimens are tested with infrared, one can observe that the specimens’ temperature field is changing. Commonly, causes of the changes are due to specimens’ plastic deformation and crack extension. But many coherent documents indicate that most specimens even has high temperature field after the peak strength. This paper put a forward that the influence of friction between the fracture planes on the specimens’ temperature field could not be ignored. Meanwhile, the paper gives a simple friction model of two blocks,. In the model, the friction surface plays the different roles to the two blocks as moving heat source and fixed heat source respectively. Those different heat sources have different effect on the blocks’ temperature field. In the end, analytic solutions of temperature change at any point of two blocks that caused by friction are given.