Arbitrarily Oriented Cracks in a Reinforced Sheet

1985 ◽  
Vol 52 (1) ◽  
pp. 13-18 ◽  
Author(s):  
C.-C. Chu

The elastic interaction between a crack and a fiber is studied for various loading conditions. Generalized from earlier work by Greif and Sanders, the present formulation is valid for arbitrary relative orientation between the crack and the fiber. Helpful design information, such as the critical loading condition and the critical fiber orientation to trigger a certain failure mode, is therefore attainable. The fundamental solutions, each associated with proper parameters and proper boundary conditions, can also be superposed to model more realistic problems.

2011 ◽  
Vol 255-260 ◽  
pp. 166-169
Author(s):  
Li Chen ◽  
Yang Bai

The eigenfunction expansion method is introduced into the numerical calculations of elastic plates. Based on the variational method, all the fundamental solutions of the governing equations are obtained directly. Using eigenfunction expansion method, various boundary conditions can be conveniently described by the combination of the eigenfunctions due to the completeness of the solution space. The coefficients of the combination are determined by the boundary conditions. In the numerical example, the stress concentration phenomena produced by the restriction of displacement conditions is discussed in detail.


Author(s):  
Ahmet Kahraman

Abstract In this paper, the dynamic behavior of a multi-mesh helical gear train is studied. The gear train consists of three helical gears, with one of the gears in mesh with the other two. An 18-degree-of-freedom dynamic model which includes transverse, torsional, axial and rotational (rocking) motions of the flexibly mounted gears is developed. Two different loading conditions are identified. For case I, the system is driven by the gear in the middle, and for case II, the system is driven by one of the gears at either end of the gear train. Gear mesh phases under each loading condition are determined. The natural modes are predicted, and effects of the helix angle and the loading condition on the natural modes are explained. The forced response, which includes dynamic mesh and bearing forces, due to the static transmission error excitation is found. Effects of loading conditions and asymmetric positioning on the response are also explored. The results suggest that the dynamic forces are lower if the number of teeth of the gear in the middle is (i) an odd number for case I type loading, and (ii) an even number for case II type loading.


1996 ◽  
Author(s):  
F. Akgun ◽  
D. Estrella ◽  
S. Rahman ◽  
B. Mitchell ◽  
A. Eustes

Author(s):  
Rabi Pathak

The Formula Student competitions are held everyyear. This paper is the result of the analysis done on the sample car design that can be presented in the Formula Student competition. The purpose of the paper is to provide a final summary on chassis analysis and structural performance. It also talks about all the important analysis that is to be done on a Formula Student car to make it safe and perform well on the track. The design has been made such that it focusses on maximum adjustability, reliability, performance, safety, weight reduction and ease of manufacturing. The analysis was done to make sure the objectives of design are fulfilled. After going through many papers, documents, blogs and videos we found that many people get confused about the loading conditions and boundary conditions for different types of tests so this paper prioritizes to make people understand about those conditions as well as about the major tests required to perform complete analysis of Formula Student cars. The weight of the chassis was calculated as 36 kg approximately according to the data obtained from design modeler of Ansys workbench as well as Solidworks. The design sustained all the loading conditions and passed all the tests. Thus, one of the objective of this paper is to help other universities and passionate students to successfully design and analyze their cars that can pass all necessary tests included in the paper. KEYWORDS—Formula Student; FEA; Boundary Conditions; Loading Conditions; Ansys; Solidworks


Author(s):  
L. Caillé ◽  
J L. Hanus ◽  
F. Delvare ◽  
N. Michaux-Leblonda

A method is proposed to solve an inverse problem in twodimensional linear isotropic elasticity. The inverse problem consists of the determination of both the entire displacement field and the boundary conditions inaccessible to the measurement from the partial knowledge of the displacement field. The algorithm is based on a fading regularization method (FRM) and is numerically implemented using the method of fundamental solutions (MFS). The inverse technique is first validated with synthetic data and is then applied to the interpretation of experimental measurements obtained by digital image correlation (DIC).


2019 ◽  
Vol 25 (8) ◽  
pp. 1470-1483 ◽  
Author(s):  
Gurwinderpal Kaur ◽  
Dilbag Singh ◽  
SK Tomar

The propagation of Love-type waves in a nonlocal elastic layer with voids resting over a nonlocal elastic solid half-space with voids has been studied. Dispersion relations are derived using appropriate boundary conditions of the model. It is found that there exist two fronts of Love-type surface waves that may travel with distinct speeds. The appearance of the second front is purely due to the presence of voids in layered media. Both fronts are found to be dispersive in nature and affected by the presence of the nonlocality parameter. The first front is found to be nonattenuating, independent of void parameters and analogous to the Love wave of classical elasticity, while the second front is attenuating and depends on the presence of void parameters. Each of the fronts is found to face a critical frequency above which it ceases to propagate. For a specific model, the variation of the phase speeds of both the fronts with frequency, nonlocality, voids and thickness parameters is shown graphically. Attenuation coefficient versus frequency for the second front has also been depicted separately. Some particular cases are deduced from the present formulation.


Author(s):  
Kian Sing Tan ◽  
Young W. Kwon

Strain rate affects the behaviors of engineering structural materials, such as metals and composites, in terms of their stiffness and strength. In particular, yield and failure strengths and strains depend on the strain rate applied to the materials. When a structural material is subjected to a typical dynamic loading, the material usually undergoes various strain rate loading conditions. Then, the main question is whether the material is going to fail or not. To the authors’ best knowledge, there has been no failure criterion proposed for a varying strain rate loading condition. This paper presents a failure criterion under non-uniform strain rate conditions. Experiments were also conducted to support the proposed failure criterion using aluminum alloy AA3003-H14. This study also investigated the failure envelopes in terms of strain rates and the normalized failure strengths. Furthermore, evaluations of various stressstrain relations under different strain rate loading conditions were also undertaken.


2015 ◽  
Vol 18 (5) ◽  
pp. 1282-1312 ◽  
Author(s):  
Aiyu Zhu ◽  
Congming Jin ◽  
Degang Zhao ◽  
Yang Xiang ◽  
Jingfang Huang

AbstractDislocations are line defects in crystalline materials. The Peierls-Nabarro models are hybrid models that incorporate atomic structure of dislocation core into continuum framework. In this paper, we present a numerical method for a generalized Peierls-Nabarro model for curved dislocations, based on the fast multipole method and the iterative grid redistribution. The fast multipole method enables the calculation of the long-range elastic interaction within operations that scale linearly with the total number of grid points. The iterative grid redistribution places more mesh nodes in the regions around the dislocations than in the rest of the domain, thus increases the accuracy and efficiency. This numerical scheme improves the available numerical methods in the literature in which the long-range elastic interactions are calculated directly from summations in the physical domains; and is more flexible to handle problems with general boundary conditions compared with the previous FFT based method which applies only under periodic boundary conditions. Numerical examples using this method on the core structures of dislocations in Al and Cu and in epitaxial thin films are presented.


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