طراحي فريم شاسي خودرو و خدمات شهري بر پايه بهينه سازي توپولوژي و طرح

چكيده انگليسي :

Design of Municipal Vehicle Chassis Frame Based on Topology and Sizing Optimization Ali Zargarian Foroushani A Zarharian@me iut ac ir Date of submission 2010 4 13 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Mohammad Reza Forouzan Forouzan@cc iut ac ir Abstract Nowadays reducing weight of products especially for the products that cause environmental pollution such as vehicles is not only an option but also an obligation In the current work design of a chassis frame of a commercial vehicle is performed in order to reduce the weight The work is dived into two parts In the first part some information regarding the technical specification of the vehicle is provided and then main targets are set Loading conditions different types of chassis frame and analysis methods are discussed Packaging of vehicle components is done in order to determine design space for topological optimization of the chassis frame In the second part topological optimization of frame is done for some target functions For investigating load paths as well as overall shape of the frame a pseudo density with values between 0 and 1 is considered for each element as the design variable By relating stiffness of each element to this pseudo density and defining the minimum compliance as the objective function and the maximum volume fraction as the constraint the elements which have less structural role are omitted during the optimization process to minimize mass of the structure Minimization compliance under multiple loading cases is a multidisciplinary optimization problem since compliance of each loading condition is an objective function that should be minimized In this work weighted sum method that minimizes linear combination of objective functions is used for minimizing weighted sum compliance But the value of each weight is determined by means of Pareto optimality concept The process is begun by defining design space which is the allowable space that chassis frame can be placed in Then the design space is meshed and suspension system which is modeled as a mechanism is attached to the frame by rigid elements After that loads and boundary conditions are applied and topological optimization is performed for different combination of weights After plotting compliance of symmetric bending against asymmetric bending for each weight combination optimal weights are determined that are related to points having minimum distance to ideal points An ideal point is a point in which each function has its minimum value but it is not an accessible point and is just for comparing other points with it After investigating the results of topological optimization three different concepts are presented for the chassis frame The beam finite element model of each concept is developed Chassis frame members are modeled in ANSYS by BEAM188 element that considers warping as seventh DOF of the beam element This element has more accurate results in comparison with shell elements Also components of suspension system are modeled using BEAM4 and COMBINE7 elements Loads are applied as concentrated forces by proper dynamic factor to consider dynamic characteristics of the forces Boundary conditions are applied at

زرگريان فروشاني، علي

طراحي فريم شاسي خودرو و خدمات شهري بر پايه بهينه سازي توپولوژي و طرح

سازه خودرو , خدمات شهري , اجزاي خودرو , تحليل شاسي