共查询到20条相似文献,搜索用时 31 毫秒
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In automobiles, the CFRP (carbon fiber reinforced plastics) has a possibility of weight reduction in automotive structures which can contribute to improve mileage and then reduce carbon dioxide. On the other hand, the safety of collision should be also made clear in the case of employing the CFRP to automotive structures. In this paper, the CFRP guarder belt equipped in the automotive door is developed and examined by an experiment and a numerical analysis for replacing the conventional steel door guarder beam. As the experimental relation of impact load to displacement for CFRP guarder belt agreed well with that of numerical result, the numerical method developed here is quite useful for estimating impact behaviors of CFRP guarder belt. 相似文献
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Mohammad M. Islam 《机械工程与自动化:英文版》2013,(9):529-542
Abstract: In a test-fixture that the authors were using, steel tabs adhesively bonded to an aluminum panel debonded before the design load on the real test panel was fully applied. Therefore, studying behavior of adhesive joints for joining dissimilar materials was deemed to be necessary. To determine the failure load responsible for debonding of adhesive joints of two dissimilar materials, stress distributions in adhesive joints as obtained by a nonlinear finite element model of the test-fixture were studied under a gradually increasing compression-shear load. It was observed that in-plane stresses were responsible for the debonding of the steel tabs. To achieve a better understanding of adhesive joints of dissimilar materials, finite element models of adhesive lap joints and ADCB (asymmetric double cantilever beam) were studied, under loadings similar to the loading faced by the test-fixture. The analysis was performed using ABAQUS, a commercially available software, and the cohesive zone modeling was used to study the debonding growth. 相似文献
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Romualdo Figueiredo de Sousa Fracisco Augusto Vieira da Silva Joao Bosco Aquino Silva Jose Carlos de Lima Junior 《机械工程与自动化:英文版》2014,(6):488-498
In the processes of manufacturing, MT (machine tools) plays an important role in the manufacture of work pieces with complex and high dimensional and geometric accuracy. Much of the errors of a machine tool are those which are thermally induced which are from internal and external heat sources acting on the machine. In this paper, a methodology for determining and analyzing the thermal deformation of machine tools using FEM (finite element method) and ANN (artificial neural networks) is presented. After modeling the machine using FEM is defined the location of the heat sources, it is possible to obtain the temperature gradient and the corresponding thermal deformation at predetermined periods. Results obtained with simulations using the software NX.7.5 showed that this methodology is an effective tool in determining the thermal deformation of the machine, correlating the temperature reading at strategic points with volumetric deformation at the tool tip. Therefore, the thermal analysis of the errors in the pair tool part can be established. After training and validation process, the network will be able to make the prediction of thermal errors just stating the temperature values of specific points of each heat source, providing a way for compensation of thermally induced errors. 相似文献
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Kazuhito Misaji Yusuke Suzuki Ayumi Takahashi Fumihiko Ide Theophane Courtois 《机械工程与自动化:英文版》2014,(4):305-310
In order to improve the mass efficiency of an automotive soundproof package, it is important to predict the middle to high frequency range of noise and vibration during vehicle operation. A hybrid method of experimental and analytical SEA (statistical energy analysis) has been applied for the prediction of air-borne noise. However, for predicting structure-borne noise, there are no definitive simulation methods that can address the soundproof specifications in an actual vehicle. Thus, in this paper, a FEM (finite element method)'SEA hybrid method is used. The FEM'SEA hybrid method predicts structure-borne noise in the middle to high frequency range. First, we explain the basic concept of the FEM'SEA hybrid method; Second, we describe our experiment to verify the analytical results of the FEM'SEA hybrid method; Third, we provide the details of the FEM model versus the FEM'SEA hybrid model; Finally, we verify the validity and availability of the FEM'SEA hybrid method through comparisons of the FEM analysis results, FEM-SEA analysis results and measured results. 相似文献
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The dynamic behaviour of power line cables have been a source of interest to researchers ever since the phenomenon was first noticed in the 1920s. Conductor oscillation is mostly caused by the dynamic forces of nature such as wind loading. This imposes a periodic force on the conductors which is highly undesirable. It is therefore important for engineers to account for the possible effect of the wind loading when designing the power line. Investigations have shown that modeling the exact dynamic behaviour of a conductor is very difficult. Based on this fact, getting the exact analytical solution to conductor vibration is difficult, which is almost impossible, hence the numerical approximation becomes an option. This paper presents the developed finite element method used to analyse the dynamic behaviour of transmission line conductors. The developed FEM (finite element method) is implemented on MATLAB. The numerical analysis using MATLAB that is presented in this paper is used to simulate the response of the conductor when subjected to external loading in the time domain. The simulation is used to analyse the transverse vibration of the conductor. The formulation of the stiffness matrix and load vector is done and the results obtained are used to evaluate the conductor's internal energy dissipation. This finite element solution is compared with the results documented in literature. This numerical simulation is also used to investigate the effects of varying the axial tension on energy dissipation within the strands. Hence, this evolved in physically appropriate energy characterization process that can be used to evaluate the conductor self-damping with respect to line contact. 相似文献
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In roller bearings, the outer ring is usually fixed and the inner ring has the rolling motion. Concerning TRB (tapered roller bearings), this motion generates forces that are transmitted to the outer ring by the tapered rollers. Thus, contact stresses occur and the number of rollers plays a major role with respect to the load distribution. This influence is analyzed in this study by the FEM (finite element method) with commercial code ABAQUS, where two models were evaluated: a common TRB and the same one but with fewer rollers. As an application, a manual automotive transmission was considered for the input loads. 相似文献
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In assemblies constructed from components manufactured with radial deviations, cross-section deviations and deviations being combination of both, there occur variable values of local stresses and displacements. Both the types of shape deviations and their values need to be taken into account in the designing process and play an important role during machine operation. They have a crucial effect on the value and scatter of maximum reduced von Mises stresses and contact stresses. Axisymmetric joints were examined, in which shafts in selected shape variants and in variable angular positions were associated with a non-deformable hole. The aspects of contact zone problems are presented using the example of numerical simulation of contact between an elliptical saddle-shaped shaft placed in a rigid, non-deformable hole in different angular positions. Occurrence of both variable relative stresses and contact stresses as well as shaft's axial shift and rotary movement resistance were demonstrated. 相似文献
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Olanrewaju Aluko 《机械工程与自动化:英文版》2014,(10):813-819
The present analysis was performed to obtain bearing strength for pinned joints in uni-directional graphite epoxy composite laminates using characteristic curve model. The characteristic dimensions used to determine the characteristic curve were evaluated using a two-dimensional finite element model that was developed in ANSYS14.5 Software. Also, two-dimensional finite element stress analysis was developed to determine the stress distribution needed to evaluate the failure. Tsai-Wu failure criterion was used in the analysis with the characteristic curve to predict bearing strength. The results of the analysis showed good agreement with experimental data. 相似文献
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Lucas Rangel de Oliveira ;Gilberto Pechoto de Melo ;Tiago Bemardes Firme ;Mariana Costa Falcao 《机械工程与自动化:英文版》2014,(5):400-402
The study of damage in rotating machineries is of fundamental interest in the fields of machine and structure design. A rotating system, supported by bearings and under some dynamic conditions, can generate a variety of problems that are encountered in many different types of rotating machines. One of these problems is the unbalance due to non-homogeneous mass distribution along the shaft. One of the techniques which are widespread today is the identification of parameters and excitation forces that may well followed by monitoring the evolution and change of possible variations of these parameters. Although several methods for the identification of unbalance excitation force are available in the literature, none of them can be considered unrestricted to be applied for all rotating systems. In this study, two methodologies to identify unknown excitations, such as unbalance, have been proposed. This project refers to the analysis of unbalanced forces from displacement parameters and speed by using methods of identification by Fourier series and Legendre polynomials together with the finite element method, state observers in reasons of the problem of absence of signs of rotational displacement, bandpass filter were used to noise suppression of the data collected from the experimental part, Quasi-Newton method to minimize a function in which the bearing stiffness and its damping are unknowns, and also the experimental verification of the methodology, using for this system owned by a rotary mechanical vibrations of the Department of Mechanical Engineering of Faculty of Engineering, campus of llha Solteira. 相似文献
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Roberto S. Carnicer Braian A. Desia Rodolfo A. Schwarz 《机械工程与自动化:英文版》2014,(10):820-827
Natural frequencies for multilayer plates are calculated by mixed finite element method. The main object of this paper is to use the mixed model for multilayer plates, analyzing each layer as an isolated plate, where the continuity of displacements is achieved by Lagrange multipliers (representing static variables). This procedure allows us to work with any model for single plate (so as to ensure the proper behavior of each layer), and the complexity of the multilayer system is avoided by ensuring the condition of displacements by the Lagrange multipliers (static variables). The plate is discretized by finite element modeling based on a primary hybrid model, where the domain is divided by quadrilateral, both for the displacement field and static variables. This mixed element for plates was implemented and several examples of vibrations have been verified successfully by the results obtained by other methods in the literature. 相似文献
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A roll-bending process that minimizes the flat areas on the leading and trailing ends of formed plates will produce more accurate and easier assemble final shapes. There are several methods of minimizing flat areas, but they are costly or difficult to apply for thick plates. This study proposes a new, simple approach that reduces these flat areas. This approach includes moving the bottom roll slightly along the feeding direction and adjusting the bottom roll location. Sensitivity analyses were performed using a developed 3D dynamic FE (finite element) model of an asymmetrical roll-bending process in the Ansys/LS-Dyna software package. Simulations were validated by experiments run on an instrumented roll-bending machine. The FE results indicate that this new approach not only minimizes the flat areas but also reduces the forming forces. 相似文献
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为了满足飞机结构件轻量化的设计要求,模拟了无人机起落架电传作动筒在飞机着陆阶段的载荷情况,对设计的电传作动筒主要承力零件进行了有限元分析。通过静力学仿真和动力学仿真,得到主要承力零件的应力云图、位移云图及应力随时间变化图,并根据相关仿真结果进行优化设计,在满足结构功能需求的情况下对电传作动筒各零件进行减重。 相似文献
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某型飞机在空中出现前起落架正常放下后无法锁定的故障,分解过程中发现驱动装置收放作动筒内一处密封圈失效。文中针对收放作动筒内密封圈的性能参数,结合前起落架的收放原理,建立了收放机构力学模型和密封圈的有限元模型,开展了失效密封圈对作动筒的工作行程、输出力、两腔压力变化等负载特性的影响分析,并给出结论,该结论可作为本次故障调查的理论依据,同时文中的分析方法对其他飞机的类似故障分析有一定的借鉴意义。 相似文献
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针对某型飞机FS380到FS500确定机身段,研究了不同冲击条件对机身结构动态响应特性的影响。建立了机身试验段的等比简化有限元模型。分析了0滚转角、带有10°左滚转角以及带有纵向加速度的情况下,垂直坠撞速度v=9.133 m/s时的冲击特性。对比分析了各种情况下机身框段的变形情况和座椅位置处的加速度-时间历程曲线。结果表明:冲击条件的改变会对机身结构的变形以及座椅处加速度的变化产生影响:左滚转角的出现会改变机身的变形量以及峰值加速度的出现时间,纵向冲击的加入会增加地板的变形量但会有限地减小座椅处的峰值加速度,采用合适的应急着陆方式能提高飞机的耐坠毁性能。 相似文献
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《机械工程与自动化:英文版》2014,(1):40-45
The present work consists of dynamic detection of damages in reinforced concrete bridges by using a MMUM (mathematical model updating method) from incomplete test data. A well suited finite element model of a repaired bridge is carried out. The diagnosis enables us to locate and detect the damage in a reinforced concrete bridge. Thus, developments of analytical predictions have been checked by modal testing techniques. Besides, the FTCS (finite time centered space) scheme is developed to solve the set of equations which can easily handle finite element matrices of a bridge model. It is shown in this study that the method is applied to detect damages as well as existing cracks in real time of a repaired bridge. To check the efficiency of the method, the repaired bridge of OuedOumazer in Algeria has been selected. It is proven that identification methods have been able to detect the exact location of damage areas to be corrected avoiding the inaccuracy from the finite element model for the mass, stiffness and loading. 相似文献