Optimization Method Of Double-column Pre-tighten Composite Structure Considering Carrying Integrity And Its Application

The double-column pre-tighten composite structure as a typical beam-column preloaded structure has been applied in forging presses or other heavy equipments. The slotting occurrence can decrease the reliability of the conventional optimization results. In order to solve this problem, an optimization method considering carrying-integrity is proposed to improve the reliability of the pre-tighten composite structure. The influence of the structure parameters and the varying load on bending slot is also investgated., the calculation equation of critical slotted preload was established the optimiazation progress of pre-tighten composite structure ensuring the carrying integrity was achieved by using Kriging-NSGA-Ⅱ algorithm, the structure optimization of forging machine double-column pre-tighten composite framework lower beam was completed by applying the optimization method,this method decreased the structure weight,enhanced the stusture strength,at the same time carrying integrity of structure was ensured.this method provided reference for optimization design of forging machine double-column pre-tighten composite structure.In the first chapter, the current research of the analysis the integrity of the prestressed composite structure in heavy equipments is reviewed and the related structure optimization is also discussed. And ultimately the contents and framework of the paper are determined.In the second chapter, the slotting process of the prestressed composite structure in forging press is analyzed. The influence of the structure parameters and the varying load on bending slot is also investgated.In the third chapter, the critical slotting are discussed during the deformation process of the double-column combined pre-tighten structure. The deformation compatibility conditions and the slotting decision conditions are merged to build the solving equations of the critical preloads causing slotting. The integral method and the loads superposition method are used to calculate the critical preload value. The critical preload value can provide a more accurate reference for imposing load to maintain the integrity of the prestressed composite structure.In the forth chapter, the critical preload value is applied in the structure optimization to maintain the integrity. The optimization model is built based on the kriging-NSGA-II method considering integrity. In the optimization process, the predict model is established with the Kriging approximation model and the NSGA method is applied to find the optimzal solutions.In the fifth chapter, the optimization method considering integrity is applied on the lower beam of the pre-tighten composite structure in forging press to verify its effectiveness. The critical load to maintain the integrity is acquired to avoid the slotting in the optimization of the prestressed composite frame in forging press. The optimization results is compared to verify the effectiveness of the proposed method.In the sixth chapter, the research achievements and innovations of this paper are summarized and the further research is put forward.