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针对薄壁齿圈的装夹变形问题,将Abaqus有限元仿真与BP神经网络技术应用到了齿圈装夹变形预测中。根据齿圈实际加工装夹情况,应用Abaqus有限元分析软件,建立了齿圈装夹变形的仿真模型,开展了齿圈装夹变形的有限元分析研究,建立了齿圈装夹力及其径向最大装夹变形之间的关系;以Abaqus有限元仿真数据作为训练样本和检验样本,借助BP神经网络良好的预测精度和非线性泛化能力,通过MATLAB神经网络工具箱,建立了基于BP神经网络的齿圈装夹变形预测数字化模型;并根据检验样本对模型进行了检验,预测值与仿真值之间的相对误差在0.05%之内。研究结果表明:建立的基于BP神经网络的齿圈装夹变形预测数字化模型是准确有效的,可以为智能化大数据加工制造环境下的齿圈装夹参数优化提供准确有效的数据。 相似文献
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基于机器视觉的正交微切屑变形系数研究 总被引:1,自引:0,他引:1
切屑变形系数是描述切削变形程度的重要参数,是计算其它切削过程参数的基础。然而宏观的切削理论和试验技术不适用于微切削技术。研究微切屑变形系数对预测加工结果、优化切削过程、控制加工参数有着重要意义。本文应用机器视觉方法获得了微切削中切屑的几何形状,找出了切削厚度、厚度变形系数、宽度变形系数与进给量、背吃刀量的变化关系,为微切削过程的控制和预测提供了理论依据。试验方法简单、精确、效率高。 相似文献
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针对薄板初始变形对焊接结构件尺寸精度的影响,提出了基于数字图像相关技术的光学检测方法,对薄板堆焊变形预测精度进行全场动态研究。首先采用结构光扫描的方法,获取焊接结构件初始变形轮廓,然后基于初始变形模型进行焊接变形预测,最后通过理想模型和初始变形模型预测数据对比,研究结构初始变形对堆焊变形精度的影响。研究结果表明:基于数字图像相关技术的测量方法是静态、动态获取焊接变形数据的有效手段;相对于理想结构模型,基于初始变形结构的模型,在单点动态和全场静态变形中具有较高的预测精度;两种模型在焊接完成后均呈马鞍形,但初始变形促进了焊接演变过程;初始变形缺陷影响了纵向残余压应力分布,是引起不同焊接变形的根本原因。 相似文献
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The calculated experimental procedures for determining the operating life of load-bearing locomotive structures are presented in a probabilistic form for evaluating and predicting their technical condition to provide grounds for the safe operation of locomotives. The procedures encompass lowcycle (in an elastoplastic deformation) and multicycle (in elastic deformations in the range of at least 107 cycles) loading of parts. 相似文献
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Analysis of the acoustic emission technique used in laboratory tests of reinforced-concrete structures 总被引:1,自引:0,他引:1
A. V. Benin 《Russian Journal of Nondestructive Testing》2006,42(12):790-793
Deformation, crack generation, and fracture of reinforced-concrete structures are studied experimentally. Acoustic emission is used as one of the testing techniques to monitor the development of these processes. The performed experimental studies confirm the possibility of using the acousticemission technique to study the accumulation kinetics of flaws in reinforced-concrete structures and theoretically predicting fracturing when it is still difficult to do so on the basis of macroscopic observations. It is established that laboratory acoustic-emission tests of reinforced-concrete samples provide the necessary experimental basis for developing the theory of the deformation and fracture of reinforced concrete. 相似文献
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V. E. Vil’deman M. P. Tretyakov 《Journal of Machinery Manufacture and Reliability》2013,42(2):166-170
The paper deals with the theoretical and experimental aspects of the study of the behavior of materials at the stage of supercritical deformation or work softening, consideration of which is important for the assessment of the durability of structures. The study results show the theoretical confirmation of the effect of the specimen configuration on the possibility of plotting the descending portions of deformation curves. It is shown that the equilibrium supercritical deformation of a material is possible if the stiffness of the loading system is sufficient. This is confirmed by the results of the uniaxial tension tests with unloading at various stages of elastoplastic and supercritical deformation. The method for interpreting experimental data obtained for the specimens of various dimensions under conditions of deformation localization are considered. 相似文献
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针对传统变形感知方法在复杂翼型结构中常见的病态、奇异等问题,提出了一种基于多翼型特征的非奇异变形重构模型。依据Timoshenko梁变形理论,采用依存插值技术离散单元位移场,建立理论截面应变与测量应变的最小二乘变分函数,推导单元节点变形与测量应变的积分重构模型。该模型的位置无关性有效消除评估截面选取不当引起的奇异,增强重构模型在复杂翼型结构中的适用性。同时,针对应变传感器服役期间常见的环境扰动,以重构精度与鲁棒性为评估指标,建立自适应多目标粒子群优化模型。实验结果表明,提出的重构模型整体测量精度较高,在机翼变形量小于20 mm范围内最大绝对误差为0.26 mm,最大相对均方根误差为0.42%;当变形量增大时,绝对误差随之增大,但相对均方根误差不超过3.5%。因此基于多翼型特征的非奇异变形重构模型能够满足机翼实时重构需求,有效扩展变形感知方法在复杂结构中的应用价值。 相似文献
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The analytical model for two-dimensional elastoplastic rolling/sliding contact proposed by McDowell is an important tool for predicting residual stress in rolling/sliding processes. In application of the model, a problem of low predicting precision near the surface layer of the component is found. According to the volumeconstancy of plastic deformation, an improved algorithm for McDowell’s model is proposed in order to improve its predicting accuracy of the surface residual stress. In the algorithm, a relationship between three normal stresses perpendicular to each other at any point within the component is derived, and the relationship is applied to McDowell’s model. Meanwhile, an unnecessary hypothesis proposed by McDowell can be eliminated to make the model more reasonable. The simulation results show that the surface residual stress predicted by modified method is much closer to the FEM results than the results predicted by McDowell’s model under the same simulation conditions. 相似文献
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A spline finite strip capability is described for predicting the buckling stresses and natural frequencies of vibration of prismatic plate structures which may be of composite laminated construction with arbitrary lay-ups. The plate structures may have general boundary conditions. The capability embraces analyses based on the use of first-order shear deformation plate theory and of classical plate theory, and utilizes substructuring procedures which include the use of superstrips. The theoretical development is not detailed since the present paper reports a very direct extension of a theoretical study developed for the analysis of single plates in an earlier paper in this Journal. A considerable range of buckling and vibration applications is documented and comparison of spline finite strip numerical values of buckling stresses and frequencies is made with results generated using the semi-analytical finite strip method and, in some cases, the finite element method. Buckled and vibrational mode shapes are presented for some applications. 相似文献
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Surface region plastic deformation of Inconel-718 nickel-base superalloy workpieces was evaluated when machined under orthogonal cutting conditions at various cutting speeds. Plastic deformation analysis was accomplished by determining the residual stress and plastic strain distributions in the surface region. The residual stresses were tensile and maximum near the surface and decreased in magnitude with an increase in depth beneath the machined surface. Similarly, the plastic strains were maximum near the surface and decreased with an increase in depth beneath the machined surface. In addition, a finite element simulation of orthogonal machining was carried out for predicting the residual stress and plastic strain distribution. In general, the trend of the curves predicted by the finite element model was similar to those found experimentally. 相似文献
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本文介绍一个用基本的质谱裂解规则来预测已知结构化合物的质谱的程序。如果给定对应某未知物的一组候选分子结构,该程序可通过预测质谱的比较来评价这些候选结构。程序采用动态描述方法存储裂解规则,可自动进行各种结构类型化合物的质谱预测。 相似文献