Strength Analysis And Optimization Of DL4100 Semi-trailer Towing Vehicle Frame

Semi-trailer towing vehicle is a kind of efficient transport vehicles. With the rapid development of economy, it plays a more and more important role in long-distance freight, so its reliability is repeatedly attracted by people's attention. Frame is an important part of semi-trailer towing vehicle, which bears all sorts of complex loads from inside and outside of vehicle, so its strength is directly related to the normal work and safety of semi-trailer towing vehicle. In addition, to conform to the trend of energy saving and environmental protection, on the base of meeting strength requirements, how to make the mass of the frame get lighter is a goal which people have been pursuing.In order to solve the frame's damage and lightweight problems, taking DL4100 semi-trailer towing vehicle frame as research object, using finite element theory and ANSYS, the static strength, modal, improvement and optimal design of the frame are analyzed deeply. This paper's main content is divided into three following parts:1) According to the different simulation on connections of the frame parts, two finite element models of the frame (model I and modelâ…¡) are established. The rivet or bolt connection is considered in model I but ignored in model II. The semi-trailer towing vehicle suspension system is also simulated. Through comparing and analyzing the two finite element models'two computed results under the working conditions of bending, bending-torsional, braking and turning, the simulation method of rivet or bolt connection is questioned and the result is got that the maximum stress value is 397.405 MPa which exceeds material maximum yield strength value 355 MPa. The weak part of the frame is also found out. Through modal analysing of the frame, the analytic result shows that the dynamic characteristic of the frame is good and it meets the design requirements of the frame basically.2) According to the analytic result on the frame's strength, corresponding improvement on the frame is made. Its maximum stress value is 270.882 MPa after improvement, which meets strength requirement. The modal analysis of the improved frame is done again and analytic result shows that the dynamic characteristic is improved. It further shows that the improved frame is feasible.3) The right longeron is parameterized modeled. Using the Optimal design principle, taking thickness as design variables, taking maximum stress as state variables, taking element total volume as target function, the right longeron is optimized by first-order method. After optimizing, the maximum stress of the right longeron is 188.33 MPa and the mazz of the right longeron is 171.7 Kg, smaller than initial 257.6 Kg, which initially reached a lightweight purpose.