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R. N. Bosire O. M. Muvengei J. M. Mutua J. K. Kimotho 《Materialwissenschaft und Werkstofftechnik》2023,54(5):554-570
The application of finite element models is a promising method for ensuring part quality during machining to accurately predict induced residual stresses and cutting forces. The present study applied Analysis System software to formulate a 3D model to predict induced residual stress and forces for AISI 1020 alloy. Taguchi method was applied in the design of the experiment with three levels and three factors selected: Cutting speed, feed rate and depth of cut. For validation, stresses are measured using an x-ray diffractometer from the surface to a depth of 0.6 mm in steps of 0.2 mm. The cutting forces are determined using a force dynamometer. Simulation results showed that cutting speed, feed rate and depth of cut contributed 94.76 %, 0.048 %, and 0.11 % respectively. The predictive model equations were statistically significant with a p-value of <0.005. The average induced residual stress on the superficial layer from the experiment and simulation were −367.7 MPa and −365.6 MPa respectively. The average residual stresses obtained at depths of 0.2 mm, 0.4 mm, and 0.6 mm were −260 MPa, −233 MPa, and −211 MPa, respectively. The proposed model offers a potential solution to reducing the costs of experimental methods. 相似文献
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S. Sun C. Dahmen B. Lao A. Bührig‐Polaczek 《Materialwissenschaft und Werkstofftechnik》2008,39(8):545-550
Macroscopic residual stresses in selectively long fiber reinforced aluminum parts The macroscopic residual stresses between reinforced and unreinforced zones in with different volumetric contents selectively (locally) long fiber reinforced aluminum samples were measured with the borehole method as well as simulated with FEM. The results indicate that there exist obvious macroscopic residual stresses in the samples, which are distributed very unequally. The residual stresses acquired from both methods agree well with one another. It was found that the macroscopic residual stresses at most locations in both the reinforced and unreinforced zones were not harmfully high. However, in the unreinforced zone very close to the boundary, a small zone of very large tensile residual stress was found parallel to the boundary. In the reinforced zone, a small zone with a quite large tensile residual stress was found in the vertical direction of the fiber. These high tensile residual stresses should be taken into consideration in structure designing and further production of the parts. The influence of fiber volumetric contents in the reinforced zone on the macroscopic residual stresses was analyzed with date comparisons. It was indicated that the fiber volumetric contents did not change the distribution trend very. However, with the increase of fiber volumetric contents the macroscopic residual stresses in the selectively long fiber reinforced samples rise. 相似文献
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S. Sun M. Rosefort A. Bäumer D. Chauhan I. Possel‐Dölken A. Bührig‐Polaczek 《Materialwissenschaft und Werkstofftechnik》2007,38(3):212-217
Residual Stress in Continuous Fibre Reinforced Aluminium Matrix Composites Prepared by Modified Investment Casting The residual stresses between matrix und fibres in the continuous γ‐Al2O3 fibre reinforced aluminium alloy (AlZn6Mg1Ag1) matrix composites prepared by modified investment casting were measured with x‐ray diffraction as well as simulated with FEM. It was indicated as expected that tensile residual stress exists in the Matrix und compressive residual in the fibre. The average value of the residual stress in both matrix and fibre in the composites is not very significant. However it is distributed very unevenly. Next to the interface between matrix and fibre there is a small zone in the matrix with relative great tensile residual stress. The effect of fibre volume percentage on the residual stress in the composite was also analysed. With increase of the fibre volume percentage the tensile residual stress in the matrix increases while the compressive residual stress in the fibre decreases. If the fibre volume percentage in the composite exceeds 65 %, the maximal tensile residual stress will reach the yield stress of the matrix alloy and local plastic deformation will occur. 相似文献
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W. Fricke 《Materialwissenschaft und Werkstofftechnik》2005,36(11):642-649
Residual stresses due to the welding process in steel structures can significantly affect the fatigue behaviour. Usually, high tensile residual stresses up to the yield strength are conservatively assumed at the weld toes. This conservative assumption can result in misleading fatigue assessments. Areas with compressive residual stresses may be present in complex structures, where the details are less critical than predicted. This is shown in the paper by the example of fillet‐welded stiffener ends, where beneficial compressive residual stresses cause the initiation of fatigue cracks at other locations in less‐strained areas. Another example for the effects of residual stresses concerns the stress initiation and propagation at a structural detail under fully compressive load cycles. Fatigue cracks are possible here due to high tensile residual stress fields. The conclusion is that the welding‐induced residual stresses should be known in advance for a reliable fatigue assessment, which becomes possible to an increasing extent by numerical welding simulation. 相似文献
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B. Denkena T. Grove A. Mücke D. Langen D. Nespor T. Hassel 《Materialwissenschaft und Werkstofftechnik》2017,48(11):1034-1039
During the regeneration of damaged components such as compressor blades, the weld repair is followed by machining processes. Excess weld material is removed in a cutting process in order to reproduce the final contour. Therefore, both processe have to be considered regarding the resulting surface and functional properties of the repaired component. In this study, bead on plate welds are produced on 10 mm Ti‐6Al‐4 V sheets using micro‐plasma welding with different levels of welding current. They are subsequently re‐contoured via ball end milling using tools of different cutting edge radii. The residual stress depth profile is measured using X‐ray diffractometry. It is shown that the final residual stress depth profile is mainly influenced by the milling process when machining with rounded cutting edges. 相似文献
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X‐ray Stress Analysis in Single Crystallites – Measuring Method and Analysis Routines The X‐ray stress analysis in single grains of a coarse grained material can be performed by using the single crystal method. In this work theoretical basics and measuring algorithms for the single crystal method are presented. Test measurements on an iron‐silicon alloy were carried out for different wave lengths and for different lattice planes. It is demonstrated that the Mo‐Kα radiation is well suited for the X‐ray stress analysis in single grains of the material investigated. 相似文献
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M. Brzoza E. Specht J. Ohland O. Belkessam Th. Lübben U. Fritsching 《Materialwissenschaft und Werkstofftechnik》2006,37(1):97-102
A coupled gas‐dynamical and thermo‐mechanical model for simulation of the gas flow, gas and specimen temperature, phase, stress, strain, and displacement transient‐fields during quenching of cutting discs and shafts of steel is introduced. The material properties (e. g. density, conductivity, heat capacity, hardness) are obtained by homogenization procedures. The material behaviour is described as an extension of the classical J2‐plasticity theory with the extension of temperature and phase fraction dependent yield criteria. The coupling effects such as dissipation, phase transformation enthalpy, and transformation induced plasticity (TRIP) are considered. Simulations were carried out for cutting discs of knives, and for shafts made of steel SAE 52100 with varying diameter. For the validation of the simulations, these work pieces were heated in a roller hearth kiln up to 850 °C, and than quenched in a field of nozzles in which the heat transfer coefficient was known and could be locally adjusted by the volume flow of each nozzle. The phase fractions, surface hardness, distortion, and residual stresses were measured. The simulated and measured results fit quite well. According to optimization‐simulations the shafts were quenched with a certain heat transfer coefficient distribution. The bigger diameter parts of the shaft were more intensively quenched by an increased gas flow so that the hardness profiles were equalized and the residual stresses at the edges were significantly reduced. 相似文献