Because of descriptive nonlinearity and computational inefficiency,topology optimization with fatigue life under aperiodic loads has developed slowly.A fatigue constraint topology optimization method based on bidirect...Because of descriptive nonlinearity and computational inefficiency,topology optimization with fatigue life under aperiodic loads has developed slowly.A fatigue constraint topology optimization method based on bidirectional evolutionary structural optimization(BESO)under an aperiodic load is proposed in this paper.In viewof the severe nonlinearity of fatigue damagewith respect to design variables,effective stress cycles are extracted through transient dynamic analysis.Based on the Miner cumulative damage theory and life requirements,a fatigue constraint is first quantified and then transformed into a stress problem.Then,a normalized termination criterion is proposed by approximatemaximum stress measured by global stress using a P-normaggregation function.Finally,optimization examples show that the proposed algorithm can not only meet the requirements of fatigue life but also obtain a reasonable configuration.展开更多
Damage to semi-rigid base asphalt pavement is related to improper matching of the pavement structure moduli.This study mainly focused on the modulus matching of structural layers and the development of a pavement stru...Damage to semi-rigid base asphalt pavement is related to improper matching of the pavement structure moduli.This study mainly focused on the modulus matching of structural layers and the development of a pavement structure optimization method.First,the modulus loss of existing pavement structures was analysed,and a three-dimensional finite element model was established based on the existing pavement.Second,the influence of the modulus of each structural layer on the mechanical response indicators and fatigue life was analysed.Based on the results,a pavement structure design method using the smoothness of the stress-strain curve as the modulus matching criterion of the structural layers was proposed.And it was found that a strain convex point was present and that the stress mutation between the structural layers was significant when the modulus matching of the pavement structure was reasonable.Further,the evaluation indicators were divided into two groups,namely,mechanical indicators and fatigue life indicators.And it was proposed an optimized pavement structure design method based on modulus matching and multi-indicator range analysis.Finally,the optimal modulus combination of pavement structure was determined by this method.The research systematically studied the influence of the modulus of each structural layer on the mechanical response and fatigue life of the pavement,and proposed the concept and specific executive criteria of modulus matching for the first time.Meanwhile,it also provided an effective optimization method for pavement structure design.展开更多
Conical picks are the key cutting components used on roadheaders,and they are replaced frequently because of the bad working conditions.Picks did not meet the fatigue life when they were damaged by abrasion,so the pic...Conical picks are the key cutting components used on roadheaders,and they are replaced frequently because of the bad working conditions.Picks did not meet the fatigue life when they were damaged by abrasion,so the pick fatigue life and strength are excessive.In the paper,in order to reduce the abrasion and save the materials,structure optimization was carried out.For static analysis and fatigue life prediction,the simulation program was proposed based on mathematical models to obtain the cutting resistance.Furthermore,the finite element models for static analysis and fatigue life analysis were proposed.The results indicated that fatigue life damage and strength failure of the cutting pick would never happen.Subsequently,the initial optimization model and the finite element model of picks were developed.According to the optimized results,a new type of pick was developed based on the working and installing conditions of the traditional pick.Finally,the previous analysis methods used for traditional methods were carried out again for the new type picks.The results show that new type of pick can satisfy the strength and fatigue life requirements.展开更多
基金Chinese National Natural Science Foundation(No.51890881)Science and Technology Project of Hebei Education Department(Nos.ZD2020156,QN2018228).
文摘Because of descriptive nonlinearity and computational inefficiency,topology optimization with fatigue life under aperiodic loads has developed slowly.A fatigue constraint topology optimization method based on bidirectional evolutionary structural optimization(BESO)under an aperiodic load is proposed in this paper.In viewof the severe nonlinearity of fatigue damagewith respect to design variables,effective stress cycles are extracted through transient dynamic analysis.Based on the Miner cumulative damage theory and life requirements,a fatigue constraint is first quantified and then transformed into a stress problem.Then,a normalized termination criterion is proposed by approximatemaximum stress measured by global stress using a P-normaggregation function.Finally,optimization examples show that the proposed algorithm can not only meet the requirements of fatigue life but also obtain a reasonable configuration.
基金supported by grant from the National Key R&D Program of China(2019YFE0117600).
文摘Damage to semi-rigid base asphalt pavement is related to improper matching of the pavement structure moduli.This study mainly focused on the modulus matching of structural layers and the development of a pavement structure optimization method.First,the modulus loss of existing pavement structures was analysed,and a three-dimensional finite element model was established based on the existing pavement.Second,the influence of the modulus of each structural layer on the mechanical response indicators and fatigue life was analysed.Based on the results,a pavement structure design method using the smoothness of the stress-strain curve as the modulus matching criterion of the structural layers was proposed.And it was found that a strain convex point was present and that the stress mutation between the structural layers was significant when the modulus matching of the pavement structure was reasonable.Further,the evaluation indicators were divided into two groups,namely,mechanical indicators and fatigue life indicators.And it was proposed an optimized pavement structure design method based on modulus matching and multi-indicator range analysis.Finally,the optimal modulus combination of pavement structure was determined by this method.The research systematically studied the influence of the modulus of each structural layer on the mechanical response and fatigue life of the pavement,and proposed the concept and specific executive criteria of modulus matching for the first time.Meanwhile,it also provided an effective optimization method for pavement structure design.
基金National Natural Science Foundation of China(Grant No.51674155)China Postdoctoral Science Foundation Funded Project(Project No.2016M592214)Natural Science Foundation of Shandong Province(Grant No.ZR2014EEM021).
文摘Conical picks are the key cutting components used on roadheaders,and they are replaced frequently because of the bad working conditions.Picks did not meet the fatigue life when they were damaged by abrasion,so the pick fatigue life and strength are excessive.In the paper,in order to reduce the abrasion and save the materials,structure optimization was carried out.For static analysis and fatigue life prediction,the simulation program was proposed based on mathematical models to obtain the cutting resistance.Furthermore,the finite element models for static analysis and fatigue life analysis were proposed.The results indicated that fatigue life damage and strength failure of the cutting pick would never happen.Subsequently,the initial optimization model and the finite element model of picks were developed.According to the optimized results,a new type of pick was developed based on the working and installing conditions of the traditional pick.Finally,the previous analysis methods used for traditional methods were carried out again for the new type picks.The results show that new type of pick can satisfy the strength and fatigue life requirements.
