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研究了回火温度对正火Q460E低合金结构钢的力学性能与组织影响.结果表明,在200℃到500℃范围内回火,力学性能相对较为稳定且具有较高的强韧性,而且屈强比也比较低,回火温度升高到600℃,力学性能虽相对较低,但钢的强韧性要比GB/T1591-1994(国标)规定的要高.分析认为:600℃回火强韧性降低幅度相对大的原因主要是粒状贝氏体的分解,碳化物的析出长大球化且分布在条状铁素体边沿,犹如上贝氏体,以及碳化物在原奥氏体晶界分布.200℃回火能够获得较高的强度和突出的韧性.回火过程就是粒状贝氏体分解变化,碳化物析出长大球化过程. 相似文献
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在Drude模型的基础上,计入金属薄膜表面对传导电子弛豫时间的影响,计算了金属的介电函数和光学常数,并利用结构特性矩阵方法计算了金属/电介质多层膜的反射率和吸收率,讨论了金属层厚度、层数对反射率和吸收率的影响 相似文献
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IntroductionElastic friction contact problems require accuratetracking of the movement of objects before and aftercontact and the interaction during contacts and correctsimulation of the frictional behavior between the con-tact surfaces. The boundary element method (BEM)[1,2]is well suited to accurately describe the variation of thefrictional contact conditions since the highly nonlineareffects only occur on the contact surface. For nonlinear frictional contact, various approacheshave been … 相似文献
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Multipole BEM for 3-D Elasto-Plastic Contact with Friction 总被引:3,自引:0,他引:3
The analysis of 3-D elasto-plastic contact with friction is a highly nonlinear problem. The elements in the contact and plastic zones should be refined to obtain accurate information about the real size,displacement, and traction in the contact zone. However, the increase in the number of degrees of freedom is limited when traditional boundary element method (BEM) is used with the larger memory size and long CPU time required for the solution procedure. This paper describes the additional mathematical friction model to the 3-D elastic multipole BEM to develop a 3-D elasto-plastic contact multipole BEM. Numerical tests show that with this new method, the needed computer memory size is only 2% of the traditional BEM model with friction, which erases large-scale computing with refined meshes and improves the computational accuracy. 相似文献
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《兽医外科手术学》是一门实践性极强的学科,要求教师在教学过程中,注重外科手术素养、外科技能素质、心理素质、职业道德素质、人文素质的培养,并需培养学生正确的临床思维能力和创新发展观,以适应现代临床兽医学诊疗的发展需要。 相似文献
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This paper presents a new mathematical model for the highly nonlinear problem of frictional contact. A programming model, multipole boundary element method (BEM), was developed for 3-D elastic contact with friction to replace the Monte Carlo method. A numerical example shows that the optimization programming model for the point-to-surface contact with friction and the fast optimization generalized minimal residual algorithm (GMRES(m)) significantly improve the analysis of such problems relative to the conventional BEM. 相似文献
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三维弹塑性摩擦接触多极边界元法 总被引:3,自引:0,他引:3
三维弹塑性摩擦接触问题是多重非线性问题,对接触区表面和塑变区的离散,须划分大量单元进行大规模运算才能获得接触位移、面力及应力场的准确信息。传统边界元法由于离散自由度所需内存大,CPU计算时间冗长,完整解题运算规模受到限制。本文在三维弹性多极留数边界元法的基础上,开发研制三维弹性数学规划型摩擦接触多极边界元法及源程序,建立三维弹塑性摩擦接触多极边界元法并研制其源程序,更新了课题组开发的原传统的三维弹塑性摩擦接触边界元法。数值试验表明,本法使计算机内存量减少近百倍,从而使细划分单元的大规模运算成为可能,并提高了计算精度。 相似文献