دانلود مقاله ترجمه شده آنالیز اجزا محدود و بهینه سازی شکل خودرو در تصادف با سرعت برخورد پایین – مجله IEEE

• فهرست مطالب:

 چکیده
۱ مقدمه
۲ مدل اجزای مدود
الف توضیح مدل
ب تجزیه و تحلیل شبیه سازی
ج اعتبارسنجی
۳ طراحی بهینه سازی
الف سطح مقطع بهینه
ب شیار بهینه

• بخشی از ترجمه:

شيارهاي مختلف برروي سطح مقطع مربعي ايجاد شد كه در شكل ۸ نشان داده مي شود كه در ان (الف) شيار مقعر و (ب) دو شيار مقعر و محدب و (ج) دو شيار مقعر وجود دارد. انرژي جذب شده مقايسه مي شود. لوله ها تحت اثر بار ضربه اي  پس از ۲۰ ميلي ثانيه  قرار مي گيرد. كه در شكل ۸ نشان داده شده است. مقايسه اوج بار تاثير بر اي لوله هاي مختلف و شيار هايش داشته است كه در جدول ۲ ديده مي شود. نتايج نشان مي دهد  كه پيك بار ها تاثيري در درجه هاي  مختلف دارد. كه به خصوص هنگامي كه شيارهاي مختلف وجد داشته باشد. در ميان انها بهترين حالت مواد(ج) است كه يك شيار دوجداره مقعر و محدب دارد. نتايج نشان مي دهد كه  جذب انرژي  در لوله جدار نازك با سطح مقطع مربعي با خط جوش مورب بديهي است  كه مي تواند بهبود را با دو شيار مقعر و محدب داشته باشد كه در آن مقدار پيك بار در حدود ۱۵۴٫۶۷ كيلونيوتون است و كاهش در حدود۵۸ % با مقايسه حالت بدون شيار به دست امده است.

• بخشی از مقاله انگلیسی:

INTRODUCTION The automobile impact has been an important problem in vehicle research field, since traffic accidents are one of the severest social problems around the world. As for in China, the death and injuries caused due to motor vehicle crashes increased year by year [1, 2]. It is therefore of great necessity to improve the safety performance of the automobile. Crashbox equipped at the front end of a car (see Fig. 1), is one of the most important automotive parts for crash energy absorption. In case of frontal crash accident, it is expected to be collapsed with absorbing crash energy prior to other body parts so that the damage of the main cabin frame is minimized and passengers may be saved [3]. Most of the research work focus on high velocity impact of automobile, only few on low speed impact at present in China [4]. However, the low velocity motor vehicle accident often happened for the traffic jam in most of the cities in China. It is therefore necessary to study the technical problems involve in low velocity impact. In the present work, the energy absorption characters of automobile crash-box at low-velocity impact are studied by using Finite Element (FE) method. And shape optimization for thin-walled tubes is proposed. II. FINITE ELEMENT MODELING A. Model Description Thin walled tubes, particularly those of square or circular cross-section, are a common type of automobile crash-box since they are relatively cheap, versatile and efficient for absorbing energy. This has led to them being used in a wide variety of impact loading applications [5]. In this paper, a finite element model was developed by using the software LS-DYNA. The tube was modeled using shell element of designation Belytschko-Tsay, which is interpreted as a quadrilateral element with four nodes, suitable for large strain analyses. After convergence adjustment an element size of 4 mm was adopted and found to produce suitable results. The axial low velocity impact of the rectangular tube (120mm long and 1.65mm thick) was studied firstly. The tube geometry and finite element mesh is illustrated in Fig. 2 (a) and (b) respectively. The base of the tube was fully fixed. A rigid plate of 1000kg, placed on the top of the tube as shown in Fig. 2 (b), impacted the tube at the velocity of 4.44 m / h. The material used was a steel of yield strength, ıy = 430MPa, density, ȡ = ۷٫۸۵ x 10-6kg / mm2 , Poisson ratio, ρ= ۰٫۳ and Young’s modulus, E = 210GPa. B. Simulation Analysis The energy absorption character of the rectangular tube on axial low velocity impact was simulated. The curve of impact load vs displacement is shown in Fig. 3. Where, the peak value of the impact load, one of the important parameter of energy absorption, is 371.45KN, much higher than the permissible value, 160KN. It is necessary to optimum the structure of the tube to improve the energy absorption characters, especially to reduce the peak value of the impact load. C. Model Validation The FE model of the tube was validated by comparing both the experimental and the FE model results. A circular cross-section tube (ĭ۷۰mm diameter, 268mm long and 1.80mm thick) was adopted for both impact test and FE simulation. Deformation results of impact test and FE model are shown in Fig. 4 (a) and (b) respectively. Table 1 provides a comparison of the main parameters obtained by the FE model and by the impact test. The curve of impact load vs. displacement for both FE model and impact test is given in Fig. 5. Results show that on average the difference of impact test and FE model results is within 10%. The good correlation of results obtained place the confidence in the subsequent analyses. III. OPTIMIZATION DESIGN A. Optimum Cross-section Shape In order to improve the energy absorption character of the crash-box, it is necessary to optimum the structure of the tube. Attention was firstly focused upon finding an optimum cross- section shape of the tube. Six types of thin-walled tubes were studied and compared. The tube cross-section geometries are illustrated in Fig. 6, where, (a) square section with diagonal welding line,(b) square section with middle welding line, (c) rectangle section, (d) hexagon section, (e) circular section, and (f) octagon section.