共查询到20条相似文献,搜索用时 15 毫秒
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应用COSMOS/M参数化有限元程序语言及Delphi面向对象高级语言,建立了490型柴油机活塞的参数化三维有限元计算分析模型及其数据输入输出处理接口,对活塞温度场及其影响因素进行了定量分析,并在此基础上,对490型柴油机虚拟故障工况下的热负荷进行了模拟计算,为故障仿真提供一种方便高效的手段。 相似文献
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Jaeyeol Lee Jeonghoon Yoo Kyunghoon Lee 《Journal of Mechanical Science and Technology》2014,28(5):1797-1802
In this research, the nano-second pulsed laser ablation process is studied using the three dimensional finite element analysis (FEA). Unlike other pulsed lasers such as femto-second or pico-second lasers, the nano-second pulsed laser can be analyzed appropriately based on the heat conduction theory and material removal approximation caused by thermal evaporation. Various process parameters such as the number of shots, laser power and wavelength and pulse width of the incident laser may affect the ablation process and we performed the parametric study and compared the simulation result with pre-existing experimental research. Finally, tendency of the ablation process is estimated using the design of experiments (DOE) and the response surface methodology (RSM). 相似文献
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H.A. Francis 《Wear》1982,76(2):221-245
A deterministic numerical model for plane-strain elastic frictionless contact between topographically anisotropic surfaces is derived, verified and demonstrated. The interface is divided into long rectangular surface elements sharing deflection nodes on the x axis bisecting the interface. The contact pressure distribution is piecewise linear from node to node. Given a digitized microtopographical profile z(x) of each surface, the model uses a partitioned Gauss-Seidel method to compute iteratively the pressure or gap at each node and hence the normal load and contact area fraction. The pressure moment is set to zero by allowing one body to rotate about the y axis. The elastic load limit of the interface is determined by monitoring the computed subsurface stresses. A uniform average pressure distribution can be achieved by bowing the input profiles to a particular convex geometry, thus enabling the model to simulate the deformation mechanics of a small region within a larger interface. The model is efficient and accurate for multiple-contact interfaces between randomly rough surfaces represented by profiles a few thousand nodes long. 相似文献
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A general nonlinear dynamics model is developed for three-dimensional flexible manipulators. A manipulator link is modelled as a beam undergoing both large gross rigid body motion and elastic deformation. The beam is discretized by the finite element method with its inertia lumped at the nodes of each element. A nonlinear strain-displacement relationship is developed to retain the geometric nonlinearity resulting from the large relative elastic deflections. The geometric nonlinearity is specifically treated so that the significance of the geometric nonlinear effects can be easily included not only in the fully nonlinear model, but also in the linearized model. Numerical results are presented to demonstrate the significant effects of geometric nonlinearity on the dynamic response of a flexible manipulator. 相似文献
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John E. Mottershead Michael LinkMichael I. Friswell 《Mechanical Systems and Signal Processing》2011,25(7):2275-2296
The sensitivity method is probably the most successful of the many approaches to the problem of updating finite element models of engineering structures based on vibration test data. It has been applied successfully to large-scale industrial problems and proprietary codes are available based on the techniques explained in simple terms in this article. A basic introduction to the most important procedures of computational model updating is provided, including tutorial examples to reinforce the reader’s understanding and a large scale model updating example of a helicopter airframe. 相似文献
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J.L. Zapico-Valle R. Alonso-Camblor M.P. González-Martínez M. García-Diéguez 《Mechanical Systems and Signal Processing》2010,24(7):2137-2159
A method is propounded in this paper to update finite element models in the field of structural dynamics. It is especially intended to solve cases for which other methods either cannot be applied or are inefficient. It is posed as the minimization of an error function defined in the time domain. The minimization is carried out by a novel adaptive sampling algorithm, which constitutes the main contribution in this work. In this algorithm, the solution is searched by sampling the parameters to be updated within a bounded space in an iterative form. The Beta distribution, which is consistent with the bounded character of the search space, is chosen for the sampling. The characteristics of the distributions are changed in each step of the process depending on the results of the previous ones. The method has been tested through a simulated dynamic model and an experimental case. In these particular cases, the performance of the proposed adaptive algorithm was better than those of other related stochastic algorithms it was compared with. 相似文献
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Leung SY Browne M New AM 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2008,222(1):145-149
Tetrahedral finite element meshes with smooth surfaces can be created from computed tomography scans of cancellous bone in order to evaluate its mechanical properties. Image processing before creation of the mesh can affect the accuracy of determined mechanical properties. For a cancellous bone analogue, threshold, mesh density and surface smoothing parameters used in mesh generation were varied and the mechanical properties predicted by the resulting meshes were compared to experimental results. This study has shown that threshold selection is vital for accurate determination of volume fraction and resulting mechanical properties. 相似文献
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为了分析圆弧螺旋型压电能量收集器的振动特性和输出特性,本文提出了一种有限元模型,可以在简化模型的同时改善结果的精度。对近似前后的圆弧型压电能量收集器进行了建模、仿真和测试,得到了圆弧螺旋型能量收集器的谐振频率、输出电压与输出功率。将圆弧型悬臂梁进行有限元分割成6~16个矩形结构悬臂梁,并对不同程度的有限元近似下圆弧螺旋能量收集器的谐振频率与输出性能进行分析,结果表明在有限元个数大于等于10时,谐振频率与输出性能相对误差较小。加工制备了2π圆弧螺旋型压电振动能量收集并进行了性能测试。测试结果表明螺旋能量收集器谐振频率为158 Hz,采取10边型有限元模型的理论谐振频率为153 Hz,相对误差为3.5%;最大输出功率的测试结果为53.5μW,最大输出功率的理论结果为55.2μW,相对误差为3.18%,理论结果与测试结果较为符合。 相似文献
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Bearing refurbishing has become a popular method of extending the life of rolling element bearings. In the refurbishing process the raceways of the bearing may be ground to remove any surface damage prior to repolishing and reassembly with larger sized rolling elements. In the current study a continuum damage mechanics finite element model was developed to quantify the damage in original and refurbished bearings. After calculating the damage accumulation for a set number of contact cycles with the original bearing geometry, refurbishing is simulated by removing a layer of the original surface. The refurbished microstructural model is then subjected to additional computational contact cycles until a fatigue crack reaches the surface, signifying failure. This model preserves the fatigue damage accumulated prior to refurbishing and evaluates its influence on the refurbished bearing fatigue life. All refurbished bearing surfaces showed a significant amount of life after refurbishing with L10 lives from the point of refurbishment, varying from 20% to 94% of the original L10 life. The results indicate that the remaining life of the refurbished bearing population is inversely related to the time before refurbishing and is proportional to the depth of the regrinding. Results obtained from this investigation are in good agreement when compared to the Lundberg-Palmgren bearing life equation modified for analyzing the life of a refurbished bearing. 相似文献
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This article employs an adaptive wear modeling method to study the wear progress in radial sliding bearings contacting with a rotary shaft. Mixed Lagrangian–Eulerian formulation has been used to simulate the contact condition between the bearing and the shaft, and the local wear evolution is modeled using the Archard equation. In the developed wear processor algorithm, not only remeshing is performed on the contact elements, but also is executed for their proximity elements. In this way the wear simulation becomes independent of the size of the contact elements. Validation was done for a laminated polymeric composite bearing. The composite has been modeled as a linear orthotropic material. The wear coefficients were obtained from flat-on-flat experiments and were applied as pressure and velocity dependent parameters in the wear processor. Finally, the effect of the clearance on the wear of the radial bearings has been studied numerically. The simulations also demonstrate how the contact pressure evolves during the wear process, and how the clearance influences this evolution. 相似文献
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A finite element based model for electrochemical discharge machining in discharge regime 总被引:1,自引:1,他引:0
Chenjun Wei Kaizhou Xu Jun Ni Adam John Brzezinski Dejin Hu 《The International Journal of Advanced Manufacturing Technology》2011,54(9-12):987-995
Electrochemical discharge machining (ECDM) is a promising hybrid process for high-performance machining of non-conductive glass. ECDM drilling has been found to have different characteristics and material removal mechanisms in discharge regime (less than 300???m in depth) and hydrodynamic regime (more than 300???m in depth); however, these regimes are never separately modeled in existing ECDM models, which leads to large prediction error, especially at low applied voltages and high machining depths. Until now, no model is particularly designed for discharge regime, where most material is removed. In this paper, a finite element based model for ECDM drilling in discharge regime is presented. Material removal subjected to a single spark was simulated using finite element method. The drilling depth evolution in discharge regime was predicted. The model predictions were compared with experimental results for validation. The fraction of power transferred to workpiece was found to be about 29% in discharge regime. 相似文献
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Covill D Guan ZW Bailey M Raval H 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2011,225(3):268-281
Thermal comfort is increasingly becoming a crucial factor to be considered in footwear design. The climate inside a shoe is controlled by thermal and moisture conditions and is crucial to attain comfort. Research undertaken has shown that thermal conditions play a dominant role in shoe climate. Development of thermal models that are capable of predicting in-shoe temperature distributions is an effective way forward to undertake extensive parametric studies to assist optimized design. In this paper, two-dimensional and three-dimensional thermal models of in-shoe climate were developed using finite element analysis through commercial code Abaqus. The thermal material properties of the upper shoe, sole, and air were considered. Dry heat flux from the foot was calculated on the basis of typical blood flow in the arteries on the foot. Using the thermal models developed, in-shoe temperatures were predicted to cover various locations for controlled ambient temperatures of 15, 25, and 35 degrees C respectively. The predicted temperatures were compared with multipoint measured temperatures through microsensor technology. Reasonably good correlation was obtained, with averaged errors of 6, 2, and 1.5 per cent, based on the averaged in-shoe temperature for the above three ambient temperatures. The models can be further used to help design shoes with optimized thermal comfort. 相似文献
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超磁致伸缩驱动器及有限元分析方法的研究 总被引:7,自引:5,他引:2
新型超磁致伸缩材料TbDyFe具有输出力大、位移分辨力高及位移范围大等特点,将其应用于微位移驱动器中,将极大的提高驱动器的性能指标,从而推动超精加工技术的发展.文中介绍了应用超磁致伸缩材料研制的驱动器的结构及性能,并利用有限元方法对建立磁-机械耦合模型进行分析,以利于计算机的模拟仿真,对驱动器进行分析及设计. 相似文献
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机床热误差是影响高精密机床加工精度的重要因素之一,而目前对机床热误差的分析比较少,以机床导轨为研究对象提出了一种结合有限元理论的导轨热误差确定方法,将数值模拟技术和实际测量实验相结合,利用实验测量数据修正有限元分析边界条件,从而得到准确的导轨热变形计算结果,证明了该热误差确定方法应用到实际机床导轨热误差确定和补偿方面的... 相似文献