Aluminum alloys are being increasingly applied in the automotive industry as a means to reduce mass. Their application to the vehicle structure is typically via a combination of either mechanical or fusion joining wit...Aluminum alloys are being increasingly applied in the automotive industry as a means to reduce mass. Their application to the vehicle structure is typically via a combination of either mechanical or fusion joining with adhesive bonding. Correspondingly, there has been a large effort in improving the adhesive bonding characteristics by changing the surface properties using different surface treatment techniques. One such method is the atmospheric arc discharge process which develops a specific surface roughness which can be leveraged to improve adhesive bonding. In this paper the effect of a textured surface by arc discharge on the failure mode and strength of adhesively bonded aluminum alloy sheets is investigated. A single-lap joint configuration is used for simulation and experimental analysis. A two-dimensional （2D） finite element method （FEM） involving the morphology of treated surfaces and using interfacial elements based on a cohesive zone model （CZM） are used to predict the joint strength which is an enabler for faster product development cycles. The influence of arc process parameters： the arc current and the torch scanning speed, on the surface morphology and joint strength are explored in this study. Specifically, the present study shows that the surface treatment of aluminum alloys by arc discharge can strongly enhance adhesive bond strength. Additionally, arc treatment not only increases the joint strength but also improves the quality of bond along the interface （transition toward cohesive failure mode）. The current FE simulation of adhesive joint using the elastic and elasto-plastic （non-linear） material properties for adherend and adhesive, respectively, and cohesive zone elements for interface shows an accurate prediction of the resulting joint strength. By inclusion of non-linear multi-scale geometry model via considering the surface topographical changes after surface treatment the FE joint strength prediction can be successfully implemented.展开更多
Particle layers tend to build up on wails in many filtration and separation processes, calling for periodic removal in order to keep the apparatus running. Important factors are the adhesion of the layer on the substr...Particle layers tend to build up on wails in many filtration and separation processes, calling for periodic removal in order to keep the apparatus running. Important factors are the adhesion of the layer on the substrate and the cohesion of the particles in the layer. Models describing such layer detachment generally assume constant and homogeneous conditions for the forces acting on the layer. But in reality detachment is extremely non-stationary concerning place and time, primarily due to changing conditions of the detaching forces on the one hand and changes in the particle layer morphology on the other. This paper describes a model and a simulation based on this model considering such transient kinetic effects, for which some computing results are presented and discussed.展开更多
文摘Aluminum alloys are being increasingly applied in the automotive industry as a means to reduce mass. Their application to the vehicle structure is typically via a combination of either mechanical or fusion joining with adhesive bonding. Correspondingly, there has been a large effort in improving the adhesive bonding characteristics by changing the surface properties using different surface treatment techniques. One such method is the atmospheric arc discharge process which develops a specific surface roughness which can be leveraged to improve adhesive bonding. In this paper the effect of a textured surface by arc discharge on the failure mode and strength of adhesively bonded aluminum alloy sheets is investigated. A single-lap joint configuration is used for simulation and experimental analysis. A two-dimensional （2D） finite element method （FEM） involving the morphology of treated surfaces and using interfacial elements based on a cohesive zone model （CZM） are used to predict the joint strength which is an enabler for faster product development cycles. The influence of arc process parameters： the arc current and the torch scanning speed, on the surface morphology and joint strength are explored in this study. Specifically, the present study shows that the surface treatment of aluminum alloys by arc discharge can strongly enhance adhesive bond strength. Additionally, arc treatment not only increases the joint strength but also improves the quality of bond along the interface （transition toward cohesive failure mode）. The current FE simulation of adhesive joint using the elastic and elasto-plastic （non-linear） material properties for adherend and adhesive, respectively, and cohesive zone elements for interface shows an accurate prediction of the resulting joint strength. By inclusion of non-linear multi-scale geometry model via considering the surface topographical changes after surface treatment the FE joint strength prediction can be successfully implemented.
基金support by the German Science Foundation (DFG)in the project SCHM 810/27 is acknowledged
文摘Particle layers tend to build up on wails in many filtration and separation processes, calling for periodic removal in order to keep the apparatus running. Important factors are the adhesion of the layer on the substrate and the cohesion of the particles in the layer. Models describing such layer detachment generally assume constant and homogeneous conditions for the forces acting on the layer. But in reality detachment is extremely non-stationary concerning place and time, primarily due to changing conditions of the detaching forces on the one hand and changes in the particle layer morphology on the other. This paper describes a model and a simulation based on this model considering such transient kinetic effects, for which some computing results are presented and discussed.
