The Effect of Wire Rope Mechanics on the Material Properties of Cord Composites: An Elasticity Approach

1994 ◽  
Vol 61 (1) ◽  
pp. 1-8 ◽  
Author(s):  
C. K. Shield ◽  
G. A. Costello

An analytical model is presented for the behavior of cord reinforced rubber composite plates taking into account the extension-twisting coupling of the cord based on an equilibrium formulation. The effect of the cord mechanics on the unidirectional lamina properties is investigated for various modulus ratios and geometries. The equations of equilibrium are derived for the unidirectional plate. Solutions are found for the following plate problems, uniaxial tension along the cord direction, uniaxial tension perpendicular to the cord direction, and pure shear. These solutions are used to obtain average material properties and to investigate the influence of cord mechanics on the plate response. For very flexible synthetic rubbers, the behavior of the unidirectional lamina exhibits a good deal of extension twisting coupling, whereas for stiffer vulcanized rubbers, the rubber acts to restrain the cords from unwinding.

1994 ◽  
Vol 61 (1) ◽  
pp. 9-15 ◽  
Author(s):  
C. K. Shield ◽  
G. A. Costello

The behavior of one-ply and two-ply laminated cord-rubber composite plates in uniaxial tension is presented. The plate mechanical properties are presented as functions of cord angle for various cord-modulus to matrix-modulus ratios. The model developed takes account of the extension-twisting coupling of the cord, as well as the exact location of the cord within the composite plate. An energy method formulation is used, and the model is solved using the Ritz method. The current results are compared to classical lamination theory results to show the limits of usefulness for classical lamination theory for this class of composite.


1976 ◽  
Vol 4 (4) ◽  
pp. 219-232 ◽  
Author(s):  
Ö. Pósfalvi

Abstract The effective elastic properties of the cord-rubber composite are deduced from the principle of virtual work. Such a composite must be compliant in the noncord directions and therefore undergo large deformations. The Rivlin-Mooney equation is used to derive the effective Poisson's ratio and Young's modulus of the composite and as a basis for their measurement in uniaxial tension.


2010 ◽  
Vol 123-125 ◽  
pp. 280-283
Author(s):  
Chang Yull Lee ◽  
Ji Hwan Kim

The post-buckling of the functionally graded composite plate under thermal environment with aerodynamic loading is studied. The structural model has three layers with ceramic, FGM and metal, respectively. The outer layers of the sandwich plate are different homogeneous and isotropic material properties for ceramic and metal. Whereas the core is FGM layer, material properties vary continuously from one interface to the other in the thickness direction according to a simple power law distribution in terms of the volume fractions. Governing equations are derived by using the principle of virtual work and numerical solutions are solved through a finite element method. The first-order shear deformation theory and von-Karman strain-displacement relations are based to derive governing equations of the plate. Aerodynamic effects are dealt by adopting nonlinear third-order piston theory for structural and aerodynamic nonlinearity. The Newton-Raphson iterative method applied for solving the nonlinear equations of the thermal post-buckling analysis


Author(s):  
X. Lachenal ◽  
P. M. Weaver ◽  
S. Daynes

Conventional shape-changing engineering structures use discrete parts articulated around a number of linkages. Each part carries the loads, and the articulations provide the degrees of freedom of the system, leading to heavy and complex mechanisms. Consequently, there has been increased interest in morphing structures over the past decade owing to their potential to combine the conflicting requirements of strength, flexibility and low mass. This article presents a novel type of morphing structure capable of large deformations, simply consisting of two pre-stressed flanges joined to introduce two stable configurations. The bistability is analysed through a simple analytical model, predicting the positions of the stable and unstable states for different design parameters and material properties. Good correlation is found between experimental results, finite-element modelling and predictions from the analytical model for one particular example. A wide range of design parameters and material properties is also analytically investigated, yielding a remarkable structure with zero stiffness along the twisting axis.


2014 ◽  
Vol 116 ◽  
pp. 273-285 ◽  
Author(s):  
Süleyman Baştürk ◽  
Haydar Uyanık ◽  
Zafer Kazancı

2011 ◽  
Vol 110-116 ◽  
pp. 113-119 ◽  
Author(s):  
Rajesh Kumar ◽  
Dharamveer Singh

The aim of this paper is to find out the randomness in the material properties on the buckling of laminated composite plate needed for the economy, safety and reliability of the structures and components in their operational life especially for sensitive Aerospace Engineering applications in hygrothermal environments. Micromechanical model has been taken for the analysis .The used methodology is a C0 finite element method based on higher-order shear deformation plate theory for deriving the standard eigenvalue problem. A Taylor series based mean-centered first order perturbation technique is used to find out the second order statistics of the hygrothermal buckling loads under different sets of environmental conditions..The numerical results for deterministic parameters are compared and validated with available literature and random parameters with independent Monte Carlo Simulation. The result shows that the plate is significantly affected by the hygrothermal buckling load.


Author(s):  
Zhijun Wu ◽  
Sayed A. Nassar ◽  
Xianjie Yang

The study investigates the pullout strength of self-tapping pedicle screws using analytical, finite element, and experimental methodologies with focus on medical device applications. The stress distribution and failure propagation around implant threads in the synthetic bone during the pullout process, as well as the pullout strength of pedicle screws, are explored. Based on the FEA results, an analytical model for the pullout strength of the pedicle screw is constructed in terms of the synthetic bone material properties, screw size, and implant depth. The characteristics of pullout behavior of self-tapping pedicle screws are discussed. Both the analytical model and finite element results are validated using experimental techniques.


1996 ◽  
Vol 118 (2) ◽  
pp. 141-146 ◽  
Author(s):  
S. Abrate

While many advances were made in the analysis of composite structures, it is generally recognized that the design of composite structures must be studied further in order to take full advantage of the mechanical properties of these materials. This study is concerned with maximizing the fundamental natural frequency of triangular, symmetrically laminated composite plates. The natural frequencies and mode shapes of composite plates of general triangular planform are determined using the Rayleigh-Ritz method. The plate constitutive equations are written in terms of stiffness invariants and nondimensional lamination parameters. Point supports are introduced in the formulation using the method of Lagrange multipliers. This formulation allows studying the free vibration of a wide range of triangular composite plates with any support condition along the edges and point supports. The boundary conditions are enforced at a number of points along the boundary. The effects of geometry, material properties and lamination on the natural frequencies of the plate are investigated. With this stiffness invariant formulation, the effects of lamination are described by a finite number of parameters regardless of the number of plies in the laminate. We then determine the lay-up that will maximize the fundamental natural frequency of the plate. It is shown that the optimum design is relatively insensitive to the material properties for the commonly used material systems. Results are presented for several cases.


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