Research On Structural Optimization Design Of Crawler Frame Of Large Rotary Drill Rig

Due to the advantages of sufficient load capacity, low ground pressure, strong adhesive to the ground and so on, crawler travelling device has been widely promoted and applied in mechanical engineering field. As one of the key components of crawler travelling device, crawler frame plays supporting and connecting role at the same time and affects travelling performance of machine. Moreover, its weight and the manufacturing cost account for a large proportion, so it is necessary to optimize the structure of the crawler frame.Take similar products as a reference, the design of crawler frame mainly modify structure when it cannot meet requirements after checking structure performance by finite element method. Structure of crawler frame designed by this way is basically fixed, design process need complicated and repetitive work, but optimal structure of crawler frame is not always found.The paper combined topology optimization and size optimization method, found optimal material distribution of designable domain and got the optimal load-carrying path based on constrains. Then on this basis, optimize structure size of crawler frame to improve material utilization to the limit, and get more reasonable and lightweight structure under the premise of satisfactory structure performance. The main contents of research are as follows:(1) This paper introduced the structure characteristic of the crawler travelling device, established virtual prototyping model of crawler travelling device in the low velocity module of Recur Dyn and analyzed performance of crawler travelling device based on the dynamics simulation. On that basis,carried out load analysis of the crawler frame for three typical working conditions named horizontal driving at a constant speed, unilateral brake steering and climbing on the basis of the results of simulation to prepare for the optimization of structure of crawler frame.(2) This paper determined the topology optimization scheme in consideration of the characteristic of crawler frame of rotary drilling rig and established the finite element model for topology optimization of crawler frame. Based on that, the paper completed the topology optimization of crawler frame in single condition with the constrains of volume reservation rate and the objective of the minimum compliances of the global strain energy.(3) On the basis of optimization parameter set in single condition, this paper solved the crawler frame optimization model in multiple loading cases and obtained optimal material distribution of crawler frame. Moreover, this paper established model of new crawler frame based on the topology optimization results to provide reasonable initial conditions for size optimization of the crawler frame structure.(4) Based on the results of topology optimization, this paper optimized structure size of crawler frame, taking thickness of key component of crawler frame as design variable and minimum volume as the objective. Determine values of thickness in consideration of three typical working conditions.(5) This paper established model of crawler frame on the basis of final optimization results, and studied mechanical property and dynamic characteristics of crawler frame before and after optimization through the static analysis and modal analysis.