排序方式: 共有26条查询结果,搜索用时 171 毫秒
1.
《Computational Materials Science》2011,50(1):167-171
In order to evaluate the flow stress and the dynamic softening characteristics of casting 42CrMo steel, isothermal upsetting experiments with height reduction 60% were performed at the temperatures of 1123 K, 1198 K, 1273 K and 1348 K, and the strain rates of 0.01 s−1, 0.1 s−1, 1 s−1 and 10 s−1 on thermal physics simulator Gleeble 1500. The flow behavior of the applied stress as a function of strain, strain rate and temperature exhibits a more pronounced effect of temperature than strain rate, and a typical characteristic of dynamic recrystallization softening. To characterize the flow behavior more factually and accurately, the traditional Fields–Backofen equation was amended, and an innovative mathematical model containing a softening item s, n-value and m-value variable functions was brought forth. The stress–strain curves calculated by the derived flow stress equation are fit with the experimental results well not only at the hardening stage but also at softening stage. 相似文献
2.
齿轮钢18Cr2Ni4WA磨削烧伤实验及仿真预测研究 总被引:1,自引:1,他引:0
18Cr2Ni4WA钢以其韧性好和强度高的特点,广泛使用于螺旋伞齿轮等重载齿轮的生产与制造。磨齿作为齿轮加工的最后工序,磨削区域较高温度场容易引起磨削烧伤发生,使加工表面质量和疲劳寿命难以保证。针对齿轮钢18Cr2Ni4WA磨削烧伤问题,设计SG砂轮磨削实验,研究其发生磨削烧伤时表面形貌、显微硬度的变化规律,并通过有限元仿真预测烧伤层深。研究结果表明:当砂轮速度为20.3 m/s、工件速度为0.03 m/s、磨削深度大于0.05 mm时工件发生磨削烧伤,随着磨削深度的增加,烧伤程度加重,磨削表面氧化层颜色由淡黄色转为褐色最后呈现青色,表面形貌由纹理清晰转为涂覆;工件产生回火烧伤时,产生硬度较低的回火索氏体;烧伤层深的仿真模拟值与实验测量值基本吻合,验证了有限元仿真对磨削烧伤预测的可行性。 相似文献
3.
传统的车辆换档液压缓冲阀主要依靠节流小孔以及弹簧的相互作用来控制离合器内油液的压力,使其在一段时间内缓慢的上升,但其调节灵活度低,适应性较差,为此首次提出采用2D数字技术应用于车辆换档缓冲领域,设计2D数字缓冲阀,利用2D数字先导阀芯产生的推力推动主阀芯运动,进而控制缓冲阀出口的油液压力。介绍2D数字缓冲阀的结构和工作原理,并建立2D数字缓冲阀的数学模型,利用Matlab和AMESim对其模型进行联合求解,最后进行仿真分析和试验研究。研究结果表明:2D数字缓冲阀的线性度为9.25%,滞环为0.106;2D数字缓冲阀输出油压实现了换档过程中离合器内油压的变化要求,其缓冲特性的控制精度达到10.52%;缓冲阀的仿真和试验结果趋势是一致的,验证了联合仿真模型的正确性。 相似文献
4.
采用多体动力学仿真软件Recurdyn建立油气悬挂式履带车辆多体动力学模型,重点对履带车辆在两种软地面上的高速转向过程进行了动力学仿真和对比分析,讨论了履带车辆在软地面高速转向的动力学特性.研究结果表明:履带车辆在软地面高速转向稳定性差,在干沙路面转向半径比黏土路面大,干沙路面的剪切阻力角比黏土路面大,造成履带受到相对更大的侧向加速度,使得履带车辆更易发生侧翻现象;转向行驶时履带张紧力变化明显,主动轮所需扭矩较大,容易发生脱轮的状况. 相似文献
5.
6.
基于多体动力学原理,根据高速履带车辆的实体结构,使用多体动力学软件Recurdyn建立履带车辆的多刚体模型,改变预张力、速度、路面等影响履带张紧力变化的因素,进行多组仿真计。对比仿真结果可知,预张紧力的增大使张紧力增大,速度的提高使履带张紧力的振动幅度变小,干沙路面张紧状况不够理想,容易出现脱轮现象。 相似文献
7.
The flow stress behaviors of squeeze casting SiCp/2A50 matrix composites were investigated by means of compression tests on a Gleeble 1500 therma1 mechanical simulator at isothermal constant strain rates ranging from of 0.001 to 1.0 with the testing temperature ranging from 350 to 500 ℃. The experiments showed that the relationship between stress and strain was obviously influenced by the strain rate and temperature. Dynamic recrystallization generally occurred at a higher temperature and a 1ower strain rate. A linear equation could be fitted between the Zener-Hollomon parameter Z and stress in the experiments. The mean value reciprocal of temperature at every true strain had a linear relation with natural logarithm of Z parameter, and the correlation coefficient, R=0.99, which was very significant by examination. The hot deformation activation energy of SiCp/2A50 matrix composites was 163.47 KJ/mol by calculation. 相似文献
8.
9.
10.