scholarly journals Analytic determination of stress fields in cross-ply symmetric composite laminates

2016 ◽  
Vol 94-95 ◽  
pp. 87-99 ◽  
Author(s):  
Wen-Yu Liang ◽  
Shen-Haw Ju ◽  
Jiann-Quo Tarn
Keyword(s):  
Composite Laminates ◽  
Stress Fields ◽  
Analytic Determination

scholarly journals Calculation of Microstresses in Textured Polycrystals With Cubic Crystal Symmetry

1999 ◽  
Vol 32 (1-4) ◽  
pp. 309-319
Author(s):  
E. A. Mityushov ◽  
S. A. Berestova
Keyword(s):  
Static Loading ◽  
Crystal Symmetry ◽  
Stress Fields ◽  
Cubic Crystal ◽  
Cubic Symmetry ◽  
Analytic Determination

The problem of the analytic determination of microstresses in textured polycrystals with cubic symmetry under general static loading has been solved. The solution is based on the expansion of macroscopic and microscopic stress fields into hydrostatic and deviatoric portions. This essentially simplifies the description of microstresses in polycrystals.

scholarly journals Enhancement of a New Methodology Based on the Impulse Excitation Technique for the Nondestructive Determination of Local Material Properties in Composite Laminates

2020 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Carlo Boursier Niutta
Keyword(s):  
Resonant Frequency ◽  
Elastic Properties ◽  
Composite Laminates ◽  
Concentrated Mass ◽  
Modal Shape ◽  
Nondestructive Determination ◽  
Material Orientation ◽  
Impulse Excitation ◽  
Clamping System

A new approach for the nondestructive determination of the elastic properties of composite laminates is presented. The approach represents an improvement of a recently published experimental methodology based on the Impulse Excitation Technique, which allows nondestructively assessing local elastic properties of composite laminates by isolating a region of interest through a proper clamping system. Different measures of the first resonant frequency are obtained by rotating the clamping system with respect to the material orientation. Here, in order to increase the robustness of the inverse problem, which determines the elastic properties from the measured resonant frequencies, information related to the modal shape is retained by considering the effect of an additional concentrated mass on the first resonant frequency. According to the modal shape and the position of the mass, different values of the first resonant frequency are obtained. Here, two positions of the additional mass, i.e., two values of the resonant frequency in addition to the unloaded frequency value, are considered for each material orientation. A Rayleigh–Ritz formulation based on higher order theory is adopted to compute the first resonant frequency of the clamped plate with concentrated mass. The elastic properties are finally determined through an optimization problem that minimizes the discrepancy on the frequency reference values. The proposed approach is validated on several materials taken from the literature. Finally, advantages and possible limitations are discussed.

Analytic Determination of Wrench Closure Workspace of Spatial Cable Driven Parallel Mechanisms

2015 ◽  
Author(s):  
Zhiyu Sheng ◽  
Joon-Hyuk Park ◽  
Paul Stegall ◽  
Sunil K. Agrawal
Keyword(s):  
Simulation Study ◽  
Null Space ◽  
Boundary Surface ◽  
Parallel Mechanisms ◽  
Analytic Determination ◽  
Structure Matrix ◽  
Feasible Solutions

This paper proposes an efficient way of determining analytically the Wrench Closure Workspace (WCW) of spatial redundant cable-driven parallel mechanisms (CDPM). The method builds upon the boundary surface equations obtained from the null space of the structure matrix of CDPM. The set of feasible solutions is obtained that satisfies positive tension in the cables. This method was applied to characterize the WCW of spatial CDPM which has redundancy of 1 or 2. A simulation study was carried out to validate the accuracy and efficiency of the method. Several advantages over conventional approaches for determining the WCW were identified through simulation.

Analytic Determination of Slip and Efficiencies of Rolling Contact C.V.T.’s With Experimental Verifications

1986 ◽  
Vol 108 (1) ◽  
pp. 72-76 ◽  
Author(s):  
J. Modrey ◽  
Y. K. Younes
Keyword(s):  
Computer Simulation ◽  
Rolling Contact ◽  
Analytic Determination ◽  
Continuously Variable Transmissions ◽  
Fluid Properties ◽  
Good Guide ◽  
Parallel Tests

Rolling contact continuously variable transmissions (C.V.T.) transmit forces through a highly viscous spot between rolling-slipping contacts. The mechanics of the spot are characterized by complex elastohydrodynamic conditions and fluid properties only partially determinable at the extreme pressures of operation. A computer simulation of the spot mechanics based on extensions of research in less complex elastohydrodynamic situations was developed. Comparisons with parallel tests on a commercial C. V. T. verify that the simulation described in a good guide to design of this class of transmissions.

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