Research On Design And Manufacturing Technology Of All-plastic Car Body Of New Energy Vehicles

With the rapid development of composite materials in the automotive industry, body plasticizing has become a goal of automobile enterprises. Body plasticizing is divided into three phases:metal parts plasticizing (such as plastic doors and plastic rear lids), metal frames plasticizing (such as body frames with composite materials) and the whole car body plasticizing. During the late 1980s in China, the fiberglass body panels produced by hand lay-up process had got the application and promotion. Currently, the preparation of plastic car bodies has been achieved abroad using online molded process, high-pressure injection molding process and vacuum compression molding process. Rotational molding process is a research direction of processing all-plastic car bodies.This study is based on a mature new energy vehicle as an object. For the goal of developing a separate frame construction via rotational molding, the UG software is used as the main modeling tool. The design principle is shape lightweight, material lightweight, manufacture lightweight, design lightweight and functional lightweight, and the objective function is man-machine maneuverability, comfort, vehicle crash safety, dynamic performance, mechanical properties and others of the all-plastic car body. The reasonability of rotational molding design is comprehensively considered, and an integrated design of an all-plastic car body in the new energy vehicle is ultimately achieved. The number of parts of the vehicle and the body mass of the vehicle are reduced, and the dynamic performance, the driving mileage and other properties of the vehicle are improved in order to make an attempt to provide a theoretical basis and technical guidance for the development, the manufacture and the industrialization of new energy vehicles.The paper studies the following work:1. The design of an all-plastic car body is suitable for the rotational molding process. This study is based on a mature new energy sample car, design processes and methods of a new energy car body are studied on the basis of the rotational molding process, and the powerful curved surfaces editing features and vehicle design automation modules of the UG software are used in order to design integrated an all-plastic car body and a modular flooring. Studies show that a plasticizing lightweight body is achieved by the following methods:highly integrated functions and components of an all-plastic car body structure are adopted; the extra manufacturing costs and manufacturing processes are minimized; universal car parts are achieved; the integrated forming technology, all-plastic door technology, all-plastic floor technology, plastic rear lid technology, plastic and steel composite technology, and "sandwich" enhanced technology are exploited together.2. The all-plastic car body is ergonomically laid out and checked. In this study, for comfort, safety, operating convenience and other ergonomic requirements for all-plastic body, internal layout tool of the car body is established, and comfort of the body, interior space of the body, body parts and body visions are analyzed. The results show that the internal structure design of all-plastic car body and body man-machine design are interdependent with each other, and different parts of the body are repeatedly coordinated and modified to meet the requirements of ergonomics, providing a kind of design criteria for optimum design of interior all-plastic car body.3. The all-plastic car body is improved by the finite element analysis and optimization. In this study, a separate frame construction is used as an object. The dynamic performance, crashworthiness, the static loading performance and torsional characteristic of all-plastic car body and chassis are analyzed via the ANSYS software and the LS-DYNA software to study the improvement programs of the dynamic performance and the mechanical properties for the all-plastic car body. The results showed that the all-plastic car body in the shape has a greater design degree of freedom than the metal body in the shape to meet the requirements of aerodynamics and lower body air resistance. The double structure of the all-plastic car body has low mechanical properties, poor collision performances, and the process and the structure of the all-plastic car body needs to be optimized in order to improve the mechanical properties and collision performances of the body so that the collision safety of the occupants is protected.4. The manufacturing technology of the all-plastic car body is researched. In this study, rotational molding manufacturing of a large complex all-plastic car body is used as an object. Rotational mold of the body, rotational molding equipment, rotational molding materials, rotational molding process and other issues are studied. The results show that the modular body mold can reduce the difficulty of rotational molding manufacturing, increase the efficiency of the body plastic molding and protect the complex feature of the body structure; the application of the shuttle rotational molding machine with 6.5 meter diameter, wireless temperature measuring technology and directional heating technology can achieve temperature control during forming of the all-plastic car body.