Investigation of paper cutting process is vital for the design of cutting tools,but the fracture mechanism of paper cutting is still unclear.Here,we focus on the cutting process of paper,including the key parameters o...Investigation of paper cutting process is vital for the design of cutting tools,but the fracture mechanism of paper cutting is still unclear.Here,we focus on the cutting process of paper,including the key parameters of cohesive zone model(CZM)for the orthotropic paper,to simulate the shear fracture process.Firstly,the material constants of the orthotropic paper are determined by longitudinal and transverse tensile test.Secondly,based on the tensile stressstrain curves,combined with damage theory and numerical simulations,the key parameters of the CZM for the orthotropic paper are obtained.Finally,a model III fracture is simulated to verify the accuracy of the model.Results show that the load-displacement curves obtained by the simulation is consistent with the test results.展开更多
The key parameters of the adhesive layer of a reinforcing patch are of great significance and affect the ability to suppress crack propagation in an Al–Li alloy patch-reinforced structure.This paper proposes a method...The key parameters of the adhesive layer of a reinforcing patch are of great significance and affect the ability to suppress crack propagation in an Al–Li alloy patch-reinforced structure.This paper proposes a method to determine the key parameters of the adhesive layer of adhesively bonded joints in the Al–Li alloy patch-reinforced structure.A zero-thickness cohesive zone model(CZM)was selected to simulate the adhesive layer’s fracture process,and an orthogonal simulation was designed to compare against the test results.A three-dimensional progressive damage model of an Al–Li alloy patch-reinforced structure with single-lap adhesively bonded joints was developed.The simulation’s results closely agree with the test results,demonstrating that this method of determining the key parameters is likely accurate.The results also verify the correctness of the cohesive strength and fracture energy,the two key parameters of the cohesive zone model.The model can accurately predict the strength and fracture process of adhesively bonded joints,and can be used in research to suppress crack propagation in Al–Li alloy patch-reinforced structures.展开更多
A sandwich beam model consisting of two face sheets and a foam core bonded by a viscoelastic adhesive layer is considered in order to investigate interfacial fracture behavior. Firstly, a cohesive zone model in conjun...A sandwich beam model consisting of two face sheets and a foam core bonded by a viscoelastic adhesive layer is considered in order to investigate interfacial fracture behavior. Firstly, a cohesive zone model in conjunction with a Maxwell element in parallel, or with a Kelvin element in series, respectively, is employed to describe the characteristics of viscoelasticity for the adhesive layer. The models can be implemented into the implicit finite element code. Next, the parametric study shows that the in- fluences of loading rates on the cohesive zone energy and strength are quite different for different models. Finally, a sandwich double cantilever beam model is adopted to simulate the interface crack growth between the face sheet and core. Numerical examples are presented for various loading rates to demonstrate the efficacy of the rate-dependent cohesive models.展开更多
基金supported by the National Natural Science Foundation of China(No.11702147)。
文摘Investigation of paper cutting process is vital for the design of cutting tools,but the fracture mechanism of paper cutting is still unclear.Here,we focus on the cutting process of paper,including the key parameters of cohesive zone model(CZM)for the orthotropic paper,to simulate the shear fracture process.Firstly,the material constants of the orthotropic paper are determined by longitudinal and transverse tensile test.Secondly,based on the tensile stressstrain curves,combined with damage theory and numerical simulations,the key parameters of the CZM for the orthotropic paper are obtained.Finally,a model III fracture is simulated to verify the accuracy of the model.Results show that the load-displacement curves obtained by the simulation is consistent with the test results.
基金Project(51575535)supported by the National Natural Science Foundation of ChinaProject(2015CX002)supported by the Innovation-driven Plan in Central South University,China+2 种基金Project(zzyjkt2013-09B)supported by the Fund of the State Key Laboratory of High Performance Manufacturing,ChinaProject(2017zzts638)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2016RS2015)supported by the Scientific and Technological Leading Talent Projects of Hunan Province,China
文摘The key parameters of the adhesive layer of a reinforcing patch are of great significance and affect the ability to suppress crack propagation in an Al–Li alloy patch-reinforced structure.This paper proposes a method to determine the key parameters of the adhesive layer of adhesively bonded joints in the Al–Li alloy patch-reinforced structure.A zero-thickness cohesive zone model(CZM)was selected to simulate the adhesive layer’s fracture process,and an orthogonal simulation was designed to compare against the test results.A three-dimensional progressive damage model of an Al–Li alloy patch-reinforced structure with single-lap adhesively bonded joints was developed.The simulation’s results closely agree with the test results,demonstrating that this method of determining the key parameters is likely accurate.The results also verify the correctness of the cohesive strength and fracture energy,the two key parameters of the cohesive zone model.The model can accurately predict the strength and fracture process of adhesively bonded joints,and can be used in research to suppress crack propagation in Al–Li alloy patch-reinforced structures.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10672027 and 90816025)the National Basic Research Program of China (Grant No. 2006CB601205)
文摘A sandwich beam model consisting of two face sheets and a foam core bonded by a viscoelastic adhesive layer is considered in order to investigate interfacial fracture behavior. Firstly, a cohesive zone model in conjunction with a Maxwell element in parallel, or with a Kelvin element in series, respectively, is employed to describe the characteristics of viscoelasticity for the adhesive layer. The models can be implemented into the implicit finite element code. Next, the parametric study shows that the in- fluences of loading rates on the cohesive zone energy and strength are quite different for different models. Finally, a sandwich double cantilever beam model is adopted to simulate the interface crack growth between the face sheet and core. Numerical examples are presented for various loading rates to demonstrate the efficacy of the rate-dependent cohesive models.
