Papers by Author: Jia Ling Yan

Abstract: The effect of metal block as the fillet on the stress distributed in weld-bonded single lap steel joint was investigated using elasto-plastic finite element method (FEM). The results from the numerical simulation showed that it is beneficial when the joints with a couple of right triangle metal block were adhered to both ends of the over lap. It is advantageous of reducing the peak stress in the adhesive layer near the ends of the lap zone in weld-bonded single lap steel joints so that the stress distribution in overlap zone was improved. The load-bearing capacity of the weld-bonded single lap steel joints may be elevated. There is no evidential difference in the effects between the steel and aluminum block.

Abstract: The influence of the fillet with different elastic modulus on the stress distributed in weld-bonded aluminum alloy single lap joint was investigated using elasto-plastic finite element method. The results show that the peak values of the stress along the mid-bondline at the points near the fillet edge were increased as the elastic modulus of the fillet increased. But at points near the both ends of the adherend in over lap zone as well as in the region of the nugget the peak stresses were decreased except longitudinal stress Sx. The peak value of Seqv decreased first, and then it increased again as the elastic modulus in fillet increased. The load-bearing capacity of the whole weld-bonded joints may be improved for the fillet with Adhesive B (825 MPa) for the relative high stress region in nugget was wider and the stress distribution in overlap zone was more uniform.

Abstract: The effect of recessing on the stresses distributed along the mid-bondline in both standard single lap joints and co-axial ones were analyzed using elasto-plastic finite element method (FEM). The results obtained show that the values of the peak stresses of all the stresses distributed in the mid-bondline were changed greatly as the preformed angle in over lap zone was about 10 0 when the high elastic modulus adhesive is used. The effect of the elastic modulus level on the stress distribution (especially the peak stresses) is small in the middle part of the lap zone. When taken the stress distributed in the middle part of the lap zone into account, there is nearly no significant difference between the peel stress distributed in the standard joint and co-axial single lap joint when the adhesives with lower elastic modulus was used. It is recommended that a co-axial joint is suitable for the recessing joint made by aluminum alloy and a higher elastic modulus adhesive.

Abstract: The influence of fillets with different geometry shape on the stress distribution in aluminum alloy weld-bonded single lap joint was investigated using elasto-plastic finite element method (FEM). The results show that it is advantageous of reducing stress concentration in adhesive layer near the ends of the lap zone in single lap weld-bonded aluminum joints and part of the stress transferring from adhesive layer to the nugget when the joints with a couple of right triangle fillets over other shapes. The load-bearing capacity of the whole weld-bonded joints may be improved. The full-triangular fillet is recommended that it be more advantageous of decreasing the stress peak value and making the stress distribution in overlap zone more uniform.

Abstract: The effect of the adhesive thickness and elastic modulus on the stress distribution in the mid-bondline of the adhesively-bonded steel/steel joint under impact loading is analyzed using 3-D finite element method (FEM). The results show that the stress distributed in bondline near the interface was significantly affected by the adhesive thickness and the elastic modulus. When the thickness increased from 1 mm to 2 mm, the values of all the stress components increased evidently along the upper edge of the adhesive but decreased significantly along the lower edge near the loading face. When the elastic modulus of the adhesive was increased, all the stresses increased along either the upper or the lower edge. It is clear that the suitable thickness and the elastic modulus of the adhesive are very important when the adhesively bonded joints subjected to the impacting load.

Abstract: The 3-D elasto-plastic finite element method (FEM) was used to analyze the thermal stress in the laminated composite (SiC/6061Al) under the condition of a temperature cycling of 200 0C-30 0C- 200 0C-30 0C. The results from the FEM analysis showed that the hysteretic peak value of the von Mises equivalent stress in the substrate 6061Al was increased significantly as the temperature loading cycles processed on but it was nearly the same after the first cycle in the interface layer SiC of the laminated composite. The elastic strain in the substrate 6061Al varied within the range of -0.15% to 0.15% and the maximum plastic deformation was equal to about 0.26 %. The results also showed that the maximum normal stress Sx was increased from 32.8 MPa to 87.9 MPa after ten cycles and the work-hardening of the substrate 6061Al occurred during the stress and strain hysteresis loop.