جستجوی مقالات مرتبط با کلیدواژه « Nonlinear finite element analysis » در نشریات گروه « مکانیک »

The appearance quality of automotive bodies is among the features which are, in recent years, significantly taken into consideration by designers throughout the world. Automotive bodies are, to a great extent, constructed from flexible sheet metal components and would deform and distorted easily by even a slight assembly force. Therefore, errors due to manufacture and assembly processes of automotive bodies lead to major deviation from the ideal product and finally affect the appearance quality and cosmetic features of the vehicle. The effect of these errors, which are commonly arisen by dimensional, geometric or assembly tolerance of the components, can be examined by tolerance analysis. As one of the key quality characteristics in vehicle design, this paper evaluates the appearance quality of automotive bodies as a function of assembly derived errors. In the proposed methodology, by means of the nonlinear finite element analysis and by presenting the surface interrogation techniques, a comprehensive approach of quality appearance evaluation of vehicles is developed. The approach is validated by a vehicle example and the results show a great consistence with practical data obtained from the production line.

Most of the studies done in low velocity impact of plates only involve plate’s response to centric impact and usually have been done in no-preload condition. In this study، nonlinear numerical elasticity analysis of eccentric low-velocity impact of rectangular sandwich plate with composite face sheets subjected to biaxial preloads، and the effect of indenter energy، the stiffness of core، the thickness of core، geometry of indenter and the existence of epoxy layers in the connection between core and face sheets on impact response are investigated. In this regard، impact 3D simulation in ABAQUS rather than approximate plate theories is utilized for extracting impact responses based on the three-dimensional theory of elasticity. Numerical results are compared with experimental data presented in other references and the numerical model is verified. The analysis results showed that the contact force increased due to the reduction of overall plate movement in the cases of eccentric impact and biaxial tension preloads، which result in augmentation of damage.

In a mechanical assembly, errors arising from part manufacturing or assembly process may cause significant variation in final assembly with respect to the ideal model and affect the quality and performance of product. In sheet metal products due to high order of compliancy of components, errors generated during assembly process are as important as parts’ manufacturing tolerances. Therefore, it is crucial to have a comprehensive model in order to analyze the assembly process of these structures and represent the relationship between part tolerances and final assembly errors. However, it should be noted that assembly processes are often complex and nonlinear in nature. In sheet metal structures, the most important factor that makes the assembly process nonlinear is contact interaction between mating parts during assembly. If this factor is disregarded and the assembly process is only represented based on linear force-displacement relationship, the model will result in part penetration and a remarkable difference between theoretical and experimental results will occur. Another important feature in sheet metal tolerance analysis is the surface continuity of components which makes the deformation of the neighboring points of a plate correlated. This paper aims to present a new methodology for tolerance analysis of compliant sheet metal assemblies in which a nonlinear finite element analysis is integrated with improved sensitivity-free probability analysis in order to account for effects of contact interaction and surface continuity of components and calculate the assembly error.The accuracy of this approach is confirmed by anexperimental casestudy and Monte Carlo simulation