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Zhang Q.,Beihang University | Cheng X.,Beihang University | Zhang J.,Beihang University | Wang S.,Beihang University | And 2 more authors.
Composites Part B: Engineering | Year: 2016

In this paper, tensile behavior of box-joint structure fabricated by resin transfer moulding (RTM) was investigated. A finite element model (FEM) of the box joint based on cohesive zone model was established to study the joint tensile behavior. Hashin failure criterion and degradation rules were applied to simulate damage modes and to predict failure strength. The FEM results show a good agreement with experimental results. Based on the model, the influences of bolt location and lap length on the joint tensile performances were analyzed. The results show that the delamination between the L-shape part and box-shape parts is the main failure mode. Bolt location affects the damage modes, ultimate load and structure stiffness of the joint, and longer lap length has a tendency to promote ultimate load and structure stiffness. © 2016 Elsevier Ltd

Cheng X.,Beihang University | Wang Y.,Beihang University | Zhang J.,Beihang University | Yang K.,Institute 306 of the 3rd Academy of CASIC | Xu Y.,Institute 306 of the 3rd Academy of CASIC
Guti Lixue Xuebao/Acta Mechanica Solida Sinica | Year: 2011

Experimental investigation was carried out on the tensile performance of combined adhesively bonded and bolted (a single row) joints for woven composites. The failure forms of the joint were analyzed with 4mm and 6mm diameter bolt hole respectively. A 3-D damage propagation model was established including non-linear touch problem to simulate the mechanical performance of the joints and the FEM results matched well with the experimental results. It is shown that the adhesive joint can be reinforced with the load-sharing of mechanical joint. The larger the bolt diameter, the more effective is the reinforcement. The analysis of tensile properties of adhesively bonded joint with more than one row of bolts in mechanical joint poses great difficulty and more precautions must be taken for its application. The obtained results and the analysis method in this paper can provide some relevant reference and technological support for combined adhesive and bolted joint design.

Cheng X.,Beihang University | Fan J.,Beihang University | Liu S.,Beihang University | Guo X.,Beihang University | And 2 more authors.
Composites Part B: Engineering | Year: 2016

In this present investigation, a novel design scheme for composite bolted π-joint is proposed, which is mainly improved in layup design. A set of joints are manufactured by resin transfer moulding (RTM) process based on the design above. A detailed investigation by experimental and numerical analysis is conducted on them to study their mechanical behavior and failure mechanism under bending load. In this work, computational models are developed by ABAQUS/Standard, with 3D progressive damage model to predict multiple damage modes in two components of joint. By validation of experimental results, it is indicated that the numerical analysis captures the failure mechanism and provides reasonable accuracy in predicting ultimate load. It is shown that the shear-out failure of lug bolt holes is the failure mode of joints. Besides that, decreasing the thickness of base panel properly will probably cause additional damage to base panel, though it has no significant effect on ultimate load of joints. Also, the location of lug bolt hole is proved to be one of the factors that will influence the load carrying ability of joints. © 2015 Elsevier Ltd. All rights reserved.

Cheng X.,Beihang University | Yang K.,Beihang University | Wang Y.,Beihang University | Xu Y.,Institute 306 of the 3rd Academy of CASIC
Lixue Xuebao/Chinese Journal of Theoretical and Applied Mechanics | Year: 2010

As widely applied to different kinds of important engineering structures, the analysis and design of composite laminate joints have been concerned by more and more technologists at home and abroad. But for the research of the plain woven composite, there are not appropriate achievements at present. In order to better the joint design and use of the plain woven laminates, it is essential to investigate their bearing properties and damage progress modes. Experimental studies were carried out on the bearing properties of hybrid plain woven laminates with G803/5224 and G827/5224 with single bolt joint. The influence of ply volume proportions and dimensions of specimens on the bearing properties was analyzed. Based on the software platform of ANSYS, a three-dimensional finite-element progressive damage model was established to simulate non-linear bearing failure behavior of these laminates, and their initial bearing strength was predicted. Meanwhile, damage criteria and stiffness attenuation rules fit for this type of laminates were put forward and proved. The numerical calculation results are coordinate with the experimental results, and it proves that this model can be used to calculate the initial bearing damage strength of hybrid-laminated plain woven fabric composite with single bolt joint. This calculation method and research results can be connected to the design and analysis of composite structures for reference.

Li Z.,Beihang University | Cheng X.,Beihang University | Wang Y.,Beihang University | Yang K.,Beihang University | Xu Y.,Institute 306 of the 3rd Academy of CASIC
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2011

The compressive properties of one-third composite cylindrical shells were tested and theoretical analyzed. The test results show that the cylindrical shells failure in buckling. The finite element method was used to establish an analysis model of the shell. The model was used for the further static strength and buckling analysis. The results show that the static strength is much higher than the buckling strength. So the shell should fail in buckling at first. This is coordinate with the test result. And the buckling strength of this model also agrees with the test results well. This model can be used to analyze the compression behavior of the integrated composite cylindrical shell and the results would provide reference for cylindrical shell structure design. Comparing the strains of the model with that of the specimen at the corresponding points under a certain compressive load, it shows that the strains match each other and indicates the efficiency of the model.

Loading Institute 306 of the 3rd Academy of CASIC collaborators
Loading Institute 306 of the 3rd Academy of CASIC collaborators