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John J. Lesko - One of the best experts on this subject based on the ideXlab platform.
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Measurement of the Timoshenko Shear Stiffness. II: Effect of Transverse Compressibility
Journal of Composites for Construction, 2007Co-Authors: Mike Hayes, John J. LeskoAbstract:This is the second of two papers devoted to the issue of measuring the Timoshenko Shear Stiffness of thin-walled composite beams. In the first paper, the effect of warping on the effective Timoshenko Shear Stiffness, as measured through bending tests, was studied. The bending test was simulated using finite-element analysis, and the results indicated that the warping effect was minimal. On the other hand, the evidence suggests that transverse flexibility may have a significant influence on the effective Timoshenko Shear Stiffness, decreasing the effective Shear Stiffness at shorter test spans. The purpose of the present study is to further investigate this effect and to explore the use of a sandwich theory to predict the measurement error. A higher-order sandwich theory, which captures the transverse strain at concentrated loads and supports, is applied to a commercially available thin-walled composite beam. The results indicate that the sandwich model does capture the decrease in the effective Shear Stiffness at short spans, and the dependence of the Shear Stiffness on span-to-depth ratio is similar to that calculated in the first paper, using the finite-element method.
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Measurement of the Timoshenko Shear Stiffness. I: Effect of Warping
Journal of Composites for Construction, 2007Co-Authors: Mike Hayes, John J. LeskoAbstract:Fiber-reinforced polymer (FRP) composite beams are increasingly finding use in construction. Due to their lower Stiffness relative to steel sections, the design of FRP structures is usually deflection controlled. Furthermore, Shear deformation can be significant in FRP beams, thus, requiring the use of the Timoshenko beam theory to estimate deflections. However, the Timoshenko Shear Stiffness can be difficult to measure. Part of the measurement error has been attributed to Shear warping effects. It has been hypothesized that warping restraints at loading points and supports increase the apparent Shear Stiffness to a degree that is significant at relatively short spans, e.g., L∕h
Mike Hayes - One of the best experts on this subject based on the ideXlab platform.
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Measurement of the Timoshenko Shear Stiffness. II: Effect of Transverse Compressibility
Journal of Composites for Construction, 2007Co-Authors: Mike Hayes, John J. LeskoAbstract:This is the second of two papers devoted to the issue of measuring the Timoshenko Shear Stiffness of thin-walled composite beams. In the first paper, the effect of warping on the effective Timoshenko Shear Stiffness, as measured through bending tests, was studied. The bending test was simulated using finite-element analysis, and the results indicated that the warping effect was minimal. On the other hand, the evidence suggests that transverse flexibility may have a significant influence on the effective Timoshenko Shear Stiffness, decreasing the effective Shear Stiffness at shorter test spans. The purpose of the present study is to further investigate this effect and to explore the use of a sandwich theory to predict the measurement error. A higher-order sandwich theory, which captures the transverse strain at concentrated loads and supports, is applied to a commercially available thin-walled composite beam. The results indicate that the sandwich model does capture the decrease in the effective Shear Stiffness at short spans, and the dependence of the Shear Stiffness on span-to-depth ratio is similar to that calculated in the first paper, using the finite-element method.
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Measurement of the Timoshenko Shear Stiffness. I: Effect of Warping
Journal of Composites for Construction, 2007Co-Authors: Mike Hayes, John J. LeskoAbstract:Fiber-reinforced polymer (FRP) composite beams are increasingly finding use in construction. Due to their lower Stiffness relative to steel sections, the design of FRP structures is usually deflection controlled. Furthermore, Shear deformation can be significant in FRP beams, thus, requiring the use of the Timoshenko beam theory to estimate deflections. However, the Timoshenko Shear Stiffness can be difficult to measure. Part of the measurement error has been attributed to Shear warping effects. It has been hypothesized that warping restraints at loading points and supports increase the apparent Shear Stiffness to a degree that is significant at relatively short spans, e.g., L∕h
Huang Yun-hua - One of the best experts on this subject based on the ideXlab platform.
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Design of Shear Stiffness of wheelsets radial device for K7 bogie
Journal of Traffic and Transportation Engineering, 2013Co-Authors: Huang Yun-huaAbstract:Through analyzing the stress and Stiffness series parallel relations of correlative structures,the geometry and Stiffness parameters determining the Shear Stiffness of wheelsets radial device for K7 sub-frame self-steering radial bogie were defined,and the mathematic calculating formula for the Shear Stiffness of wheelsets radial device was established.Based on vehicle system dynamics analysis technology,the required Shear Stiffness of wheelsets radial device was determined as 11 MN·m-1.Considering the practical constrained conditions of bogie structures,the matching design of geometry and Stiffness parameters for the components of wheelsets radial device was carried out.First of all,the diagonal brace angle and axial tension-compression Stiffness of link bar were respectively determined as 42° and 150 MN·m-1.Further,the required structural transverse Stiffness of sub-frame,deduced by the mathematic calculating formula of Shear Stiffness,should not be below 23.6 MN·m-1.Then,aiming at the requirement of the parameters,the corresponding structural design of sub-frame was carried out.Considering the contact fitting relations among different components,the high-precise nonlinear FE assembly analysis model of wheelsets radial device was established.Calculation result shows that the final structural transverse Stiffness is 24 MN·m-1,so the design requirement for the Shear Stiffness of wheelsets radial device is achieved.The calculated Shear Stiffness is 11 MN·m-1 and equals to the required design value,so the reliability of mathematic calculating formula and design method for the Shear Stiffness is verified.
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Calculating Method of Shear Stiffness of Wheelsets Radial Device for Sub-frame Bogie
Journal of the China Railway Society, 2013Co-Authors: Huang Yun-huaAbstract:The Shear Stiffness of wheelsets radial device is the key technical parameter of the sub-frame bogie.It directly determines the hunting stability of car and also has important effect on the curve negotiating ability.Through analyzing the correlative structure stress and Stiffness series parallel relations,the geometry and Stiffness parameters which determine the Shear Stiffness of wheelsets radial device were defined,the mathematic calculating formula was then established and its accuracy was verified by using the high precise FE model.This mathematic calculating formula provides necessary theoretical support for the parameter design of the Shear Stiffness of wheelsets radial device.
Seyed Rasoul Atashipour - One of the best experts on this subject based on the ideXlab platform.
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transverse Shear Stiffness of corrugated core steel sandwich panels with dual weld lines
Thin-walled Structures, 2017Co-Authors: Peter Nilsson, Mohammad Alemrani, Seyed Rasoul AtashipourAbstract:Advances in the field of laser welding have recently enabled the commercial production of all-steel sandwich panels with a continuous and robust connection between the core and the face plates, even for plate thicknesses over 10 mm. This allows for the application of the high-performance steel sandwich panel in several fields, such as civil structures. In this paper, an analytical model is presented to determine the transverse Shear Stiffness of corrugated core steel sandwich panels with dual weld lines. The derivation is based on the direct Stiffness method (DSM). At the welded connection between the core and the faces, a rotational spring is included in the structural model, as the idealised rigid connection is unable to properly capture the mechanical interaction between the constituent plates. Both bending and Shear deformation in the cross-sectional constituent members is taken into account. The model is shown to have high precision in terms of predicting the transverse Shear Stiffness when compared with numerical analyses. Furthermore, high precision is also shown when it comes to predicting normal stresses in the constituent members of the panel with respect to Shear action. In a case study included in this paper, the impact of having two weld lines compared with a single weld was studied, together with the effect of the distance between the welds. The results show a large impact with respect to Shear Stiffness and stresses in the constituent plates. This paper focuses on laser-welded corrugated core steel sandwich panels, but the presented model can also be used for analyses of general continuous core shapes and other isotropic materials.
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A realistic model for transverse Shear Stiffness prediction of composite corrugated-core sandwich elements
International Journal of Solids and Structures, 2017Co-Authors: Seyed Rasoul Atashipour, Mahmoud EmraniAbstract:Several previous studies of the transverse Shear Stiffness of corrugated-core sandwich elements have demonstrated that the existing analytical formulations significantly overestimate this property, especially when these lightweight elements are made of composite sub-elements. Due to the recent widespread fabrication and use of composite sandwich elements in many fields of application, a more accurate and reliable formulation is needed. This paper deals with an accurate analytical model for predicting the transverse Shear Stiffness of composite sandwich elements with a structural corrugated core. The effect of the directional material properties of the sub-elements, including face sheets and core, as well as the effect of a low Shear modulus in composite material constituents of the sub-elements, is taken into account. It is shown that the transverse Shear Stiffness of corrugated web core elements is considerably lower than that predicted by the existing formulations. The present solution provides much more realistic results, especially when the corrugated-core sandwich is made of composite constituents with low Shear moduli. Different combinations of the main orthotropic material orientation of the faces and core are studied comparatively for different composite material choices corresponding to an innovative timber composite floor case. It is demonstrated that the planar direction of the main orthotropic material orientation of the core has a significant influence on transverse Shear Stiffness, whereas that of the faces is less important. Several finite element comparisons are made to ensure the reliability of the developed formulation. The importance of the disregarded Shear deformation effects on the transverse Shear Stiffness component versus different geometrical parameters of the sandwich element is studied and discussed.
Mahmoud Emrani - One of the best experts on this subject based on the ideXlab platform.
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A realistic model for transverse Shear Stiffness prediction of composite corrugated-core sandwich elements
International Journal of Solids and Structures, 2017Co-Authors: Seyed Rasoul Atashipour, Mahmoud EmraniAbstract:Several previous studies of the transverse Shear Stiffness of corrugated-core sandwich elements have demonstrated that the existing analytical formulations significantly overestimate this property, especially when these lightweight elements are made of composite sub-elements. Due to the recent widespread fabrication and use of composite sandwich elements in many fields of application, a more accurate and reliable formulation is needed. This paper deals with an accurate analytical model for predicting the transverse Shear Stiffness of composite sandwich elements with a structural corrugated core. The effect of the directional material properties of the sub-elements, including face sheets and core, as well as the effect of a low Shear modulus in composite material constituents of the sub-elements, is taken into account. It is shown that the transverse Shear Stiffness of corrugated web core elements is considerably lower than that predicted by the existing formulations. The present solution provides much more realistic results, especially when the corrugated-core sandwich is made of composite constituents with low Shear moduli. Different combinations of the main orthotropic material orientation of the faces and core are studied comparatively for different composite material choices corresponding to an innovative timber composite floor case. It is demonstrated that the planar direction of the main orthotropic material orientation of the core has a significant influence on transverse Shear Stiffness, whereas that of the faces is less important. Several finite element comparisons are made to ensure the reliability of the developed formulation. The importance of the disregarded Shear deformation effects on the transverse Shear Stiffness component versus different geometrical parameters of the sandwich element is studied and discussed.