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The Influence Analysis of Stiffness on Stringer Layout and Dimension of Full Composite Wing Sheng-jun QIAO, Hang-shan GAO, Fu-sheng WANG, Zhu-feng YUE Department of Engineering Mechanics, Northwestern Polytechnical University, Advanced Material Testing Center, Xi′an 710129, China Email: qiaoshengjun123@163.com Key words: Composite; Stiffness; Stringer; Layout; Dimension Abstract: The present study aimed at obtaining torsional stiffness, bending stiffness and stiffness center position of full composite wing using thin wall structure mechanics theory.
Acknowledgements This study is supported by the National Natural Science Foundation (No: 51175424), the 111 Project (No: B07050) and the Basic Research Foundation of Northwestern Polytechnical University (No: JC201238).
Corresponding author Sheng-jun QIAO, Dr., Tel: +86 29 88431002, Fax: +86 29 88431002, E-mail address: qiaoshengjun123@163.com References [1] M Abdo, R L Heureux, F Pepin and F Kafyeke: CASI 16th Aerospace structures and materials symposium, Montreal, Quebee (2003)
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The structural optimization can be classified into the following three classes: (1) The topological optimization was the first one [ 7-8]; (2) The second was the parameter optimization[1-5] where the parameters of structures, such as the used material constants (Young’s modulus E, mass density ρ), cross sectional parameters (moment of inertia, torsional constant, height, width, and thickness), can be taken as the design variables, and a minimum weight the objective function with the given constrains; (3) The third was the shape optimization in which the geometry of the structure is varied to obtain the optimal shape[6-8].
The structural parameters are given as follows: the length is 5m, the width is 4m, and the height is 6m; the initial thickness of shell is, the Young’s modulus of the used material is Pa; the four columns of the bunker are fixed on the ground.
Fig.4 Layout of stiffeners after layout optimization Fig.5 The stress and the displacement of the bunker (14) After 35 iterations of the DFP method, the mass of the bunker reduce form to , save material 22.6% as Fig 8, the maximum of stress of the structure is . maximum of displace in X direction is; maximum of displace in Y direction is .
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Interval target have multilayer, sunder armor play every through a layer of consumption of energy, also leave gaps between each layer, can fill materials or use of the air.
The experimental device Figure 1 shows the experimental device, the interval value of depth is 100 mm; The thickness of the steel plate material is A3 steel, each layer is 4 mm.
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Constitutive relationship.The ideal of elastic-plastic to rock materials and the Mohr-Coulomb yield criterion[9] were used in numerical simulation process.
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Assuming the materials of the hinge does not have deformation of material nonlinearity under force, under force-coupling, the center of rotation of this flexible Hooke hinge has no drift and the two outer rings has little coupling while rotating.
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The property of rope is determined by its raw materials and the processing method.
Experiment Materials.
Raw materials are untwisted and twisted polyester multifilament that is composed of 200 monofilaments.
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, （1） , （2） Among them, the lateral earth pressure stress, unit; H for soil nail wall height, the unit m; For the first layer of soil nail distance on the top of the wall height, unit m; As the coefficient of earth pressure. 2) soil nailing material tensile resistance （3） Among them, for the nail material diameter, the unit m; For the nail material tensile strength design value, unit; Ⅱ reinforcement, mm,；mm,。
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The material of the spindle shaft is 40Cr.
The eccentricity ratio of journal is .
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