簧片式硅弹性膜应力分布的计算和加速度传感器的优化设计

为了提高我们已研制成功的新型簧片式硅加速度传感器的性能,用有限元法计算了不同形状和尺寸的质量块在４０ｇ值加速度作用下产生的应力分布,使我们优选了最佳的质量块设计方案,显著地提高了灵敏度,取得了与理论计算符合得很好的实验结果。     

离心式旋转机械轴向力在线监控装置测力弹性元件的优化设计

文中对离心式旋转机械轴向力在线监控装置作了简单介绍,然后详细介绍了一种离心泵轴向力在线监控装置测力弹性元件的优化设计,为了保证测力传感器的性能,采用有限元法计算了不同结构及尺寸的弹性元件在轴向力F＝39．2kN时的应力、应变及垂直位移的分布,在此基础上优选了最佳的弹性元件结构及最佳的电阻就片贴片位置,显著地提高了测力传感器的灵敏度,并通过实验得到了验证。     

冷挤压模受内压作用应力分布规律的研究

对冷挤压模受内压作用应力分布规律的研究,能避免凹模在使用时发生早期的断裂失效,为组合凹模的设计和应用提供一定的依据。采用有限元分析软件对转子冷挤压模进行建模,在此基础上,模拟了在整体内压和局部内压下凹模的受力情况,并对模拟结果进行分析比较,得出了不同内压作用时凹模应力的分布规律。     

气门偏心对其应力分布的影响

在气门偏心落座力学模型的基础上,采用有限单元法分析了在不同偏心条件下的气门偏心对其应力状态的影响.结果表明,落座偏心对气门应力的影响很大,特别是随着偏转程度的加大,气门头部的变形也呈现明显的增大趋势;在偏转角一定的前提下,气门表面应力将随导管长度的增长而增大.     

使用薄膜湿敏元件的湿度控制器的设计

介绍了一种以Ｔａ２Ｏ５薄膜ＭＯＳ型湿敏元件为核心的湿度控制电路。该电路性能稳定,易于调节,应用广泛。     

高速空心滚子轴承的性能研究

根据接触力学理论,利用有限元软件ABAQUS,合理建立了空心圆柱滚子轴承的分析模型,研究了某高速空心滚子轴承的应力分布情况,并对滚子的空心度进行了优化设计.结果表明:在一定工况条件下,只要空心度合适,空心圆柱滚子轴承的应力分布情况要远好于实心滚子轴承.研究结果为高速空心圆柱滚子轴承的设计提供了指导.     

A study of the development of the stress optic law of photoelastic experiment considering residual stress

Photoelastic experiment has two significant problems. The first problem is manufacturing a model specimen for complicated shapes of structures. The second problem is residual stress contained in the photoelastic model material. In this paper, the stress optic law that can be effecitvely used on photoelastic model materials with residual stress is developed. By using the stress optic law as developed in this research, we can obtain good results in photoelastic experiments using model material in which residual stress is contained. It is assured that the stress optic law developed in this research is useful. Therefore, it is suggested that the stress optic law considering residual stress can be applied to the photoelastic experiment for the stress analysis of the composite materials or bi-materials in which the residual stress is easily contained.     

Finite element analysis of transient dynamic viscoelastic problems in time domain

In this paper, the simplified and stable finite element method is presented for the time domain analysis of the transient dynamic viscoelastic problems, for which the weak form is obtained by applying the Galerkin's method to the equations of motion in time integral which do not contain the inertia terms explicitly, but the inertia effect is taken into account, and discretized spatially to obtain the semidiscrete equations in time integral. In the temporal approximation, only the time interpolation functions are used for approximating the dependent variables on the divided time axis, while the time integration schemes such as the Newmark and Houbolt methods are not necessary in contrary to the conventional approach. To show the validity and applicability, two-dimensional examples are given and solved for the displacements and stresses, especially for the dynamic stress concentrations by the wave diffraction, which are discussed in detail at the aspect of the viscoelastic damping. To the authors' knowledge, no previous results except for the test example exist in the literature.     

A study on the prevention of cracks on the trepan area of motor bearing

Trepan prevents the wear of the inside part of a bearing when the initial shaft rotates. It continuously contacts with the eccentric part of the shaft in rotation and is loaded repeatedly. Therefore, even if an early crack of a trepan part is small, the crack may progress by the repeated load. If the crack progresses, very small chips come out. This is put in the rotor and prevents the rotation of the compressor. There can be leaks in a microgroove and extreme wear can occur due to lack of oil on the surface contact part. Therefore, this study was carried out to compare and investigate the trepan strength and deflection characteristics between trepan locations and dimension changes using the finite element method and search a motor bearing for a model with bigger stiffness of a trepan part and the same deflection.     

一种圆锥面无键联接接触压力和应力的解析计算方法

推导了计算圆锥无键联接的接触压力的解析公式,给出了心轴和套筒轴的径向应力、轴向应力、切向应力、Mises等效应力以及压入轴向力的方程。对解析解与等效直径的圆柱面无键联接近似解法、有限元法的计算结果进行了比较。在不考虑端部应力集中时,3种方法计算出的接触压力和Mises等效应力结果差别不大。进一步验证了近似解法的可行性,并为计算圆锥联接传递的扭矩和胀紧套的应力分析提供了依据。     

基于ANSYS的自动模切机主机墙板的应力分析和结构优化

在正常工作情况下,高速自动模切机的主机墙板会受到很大的冲击,这会大大影响到模切精度,导致产品质量严重下降。应用有限元分析软件ANSYS对其进行有限元分析,掌握其应力和变形的分布情况,并在有限元分析的基础上进行结构优化,使得优化后的结构在刚度和强度上有很大的提高,从而有针对性地解决实际问题。     

基于ANSYS的自动模切机主机墙板的应力分析和结构优化

在正常工作情况下，高速自动模切机的主机墙板会受到很大的冲击，这会大大影响到模切精度，导致产品质量严重下降。应用有限元分析软件ANSYS对其进行有限元分析，掌握其应力和变形的分布情况，并在有限元分析的基础上进行结构优化，使得优化后的结构在刚度和强度上有很大的提高，从而有针对性地解决实际问题。     

离心机转鼓有限元应力分析

这里用VisualNastran4D2002有限元分析软件对离心机转鼓进行了应力分析,较方便地找出了危险点所在的部位,通过对危险点所在的部位进行局布加强,并用有限元分析软件进行应力计算和校核。     

Thermo-viscoelastic residual stress analysis of metal liner-inserted composite cylinders

One of the most significant problems in the processing of composite material is residual stress. The high residual stress may cause cracking in the matrix without external loads and degrade tile integrity of composite structures. In this Study, thermo-viscoelastic residual stresses occurred in an aluminum liner-inserted composite cylinder are investigated. This type of the structure is used for rocket fuselage due to the convenience to attach payloads and equipment to the metal liner by machining. The time and degree of cure dependent thermo-viscoelastic constitutive equations are developed and coupled with a thermo-chemical process model. Thee equations are solved with the finite element method to predict the residual stresses in the composite cylinder and also in the interface between the liner and file composite dining cure.     

一种圆锥面无键联接接触压力和应力的解析计算方法

推导了计算圆锥无键联接的接触压力的解析公式,给出了心轴和套筒轴的径向应力、轴向应力、切向应力、Mises等效应力以及压入轴向力的方程.对解析解与等效直径的圆柱面无键联接近似解法、有限元法的计算结果进行了比较.在不考虑端部应力集中时,3种方法计算出的接触压力和Mises等效应力结果差别不大.进一步验证了近似解法的可行性,并为计算圆锥联接传递的扭矩和胀紧套的应力分析提供了依据.     

A biomechanical study of osteoporotic vertebral trabecular bone: The use of micro-CT and high-resolution finite element analysis

Osteoporosis is one of the most dangerous skeletal diseases in relation to the highest fracture risk in vertebral bones. A considerable amount of work has been done to investigate the biomechanical characteristics of osteoporotic vertebral trabecular bone. Previous researchers studied the elastic characteristics using a micro-finite element (micro-FE) model, used to analyze realistic trabecular architectures in full detail, based on micro-computed tomography (μCT). Since osteoporotic compression fracture is closely associated with the mechanical characteristics of the vertebral trabecular bone and there were few micro-FE models to account for all of the elastic and plastic characteristics in vertebral trabecular bone, this study analyzed the effect of voxel resolution on the plastic characteristics as well as the elastic characteristics of three-dimensional (3D) osteoporotic lumbar trabecular bone models. Also, we evaluated the effect of specimen geometry on this problem. It has been reported that a cubic specimen with side length 6.5mm was suggested as standard specimens for the experimental test of trabecular bone. Current study examined whether or not the effect of the specimen geometry on the experimental test may be also applied to the simulated compression test of trabecular bone specimens. The experimental test employing the rapid prototyping (RP) technique and INSTRON test machine is performed to indirectly validate the results of the simulated compression test by micro-FE analysis. The review finished with the verification about the effects of the simulated compression test.     

振动时效过程模拟与分析

由于缺乏对振动时效机理的有效解释,通过振动时效消除残余应力的方法一直未得到广泛应用。采用有限元法对焊接件残余应力的产生及振动消除过程进行了数值模拟,分析了激振力和激振频率等振动时效工艺参数对残余应力消除程度的影响。仿真结果表明,无论构件是否达到共振状态,只有产生一定的微观塑性变形残余应力才能得以释放;一阶模态能在最小的激振力下消除残余应力,是振动时效的最佳选择,而在其它频率,应力消除率取决于激振力的大小。     

轧机压下螺母承载特性的有限元计算和分析

压下螺纹副是高负荷中厚板轧机大行程辊缝调节所必需的组成装置之一,其中重量大、造价高且刚度较小的的压下螺母,由于承受大冲击载荷而成为易损零件。基于ANSYS有限元计算平台,建立了轧机压下螺纹副的1/2三维实体模型;对承受轴向载荷的压下螺纹副进行三维有限元数值计算,得到并分析了轧机压下螺母的轴向载荷分布特性。并分别计算得出了轧机压下螺母的牙厚比、基体厚度、螺牙承载面倾斜角及摩擦系数对压下螺母螺牙根部的等效应力分布的影响。为轧机压下螺纹副的优化设计,提高压下螺母的使用寿命提供了参考依据。     

Prediction of residual stress distribution in multi-stacked thin film by curvature measurement and iterative FEA

In this study, residual stress distribution in multi-stacked film by MEMS (Micro-Electro Mechanical System) process is predicted using Finite Element method FEMi. We develop a finite element program for residual stress analysis (RESA) in multi-stacked film. The RESA predicts the distribution of residual stress field in multi-stacked film. Curvatures of multistacked film and single layers which consist of the multi-stacked film are used as the input to the RESA. To measure those curvatures is easier than to measure a distribution of residual stress. To verify the RESA. mean stresses and stress gradients of single and multilayers are measured. The mean stresses are calculated from curvatures of deposited wafer by using Stoney’s equation. The stress gradients are calculated from the vertical deflection at the end of cantilever beam. To measure the mean stress of each layer in multi-stacked film, we measure the curvature of wafer with the left film after etching layer by layer in multi-stacked film.     

少齿差行星齿轮齿根弯曲应力计算方法研究

少齿差齿轮副在啮合时由于轮齿受载产生变形可能引发多对齿同时接触承载的情况[1],啮合齿对实际承担的载荷将下降。少齿差齿轮副啮合时存在多对齿同时接触承载的现象,且由于内外齿轮齿廓的凹凸曲率非常接近,啮合时齿面接触面积较大,接触力为分布力,在计算齿根弯曲应力时不宜按集中力处理,这些情况使得准确计算少齿差齿轮副的齿根弯曲应力变得复杂。现以大量有限元计算分析为基础,综合考虑多对齿同时接触承载这一情况,建立了适用于少齿差齿轮副齿根弯曲应力的计算方法,并进行了实验验证。