Revisiting the bearing stresses in webs of crane runway girders under wheel loads

2018 ◽  
Vol 21 (12) ◽  
pp. 1792-1801
Author(s):  
Tong Genshu ◽  
Xuan Zejun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fourier Transform ◽  
Shear Deformation ◽  
Infinite Plane ◽  
Element Analysis ◽  
Closed Form Solutions ◽  
Bearing Stress ◽  
The Fourier Transform ◽  
The Moment

This article revisited the problem of local bearing stress in webs of I-section girders supporting overhead cranes. Finite element analysis was carried out to determine the equivalent bearing length. It was found that the moment of inertia of the rail and the web thickness of the girder are the two predominant factors. The equivalent bearing lengths by the finite element analysis were found to be significantly smaller than that predicted by the formula in various codes. Analysis revealed that the differences come from the shear deformation in the rail and the load position on the rail. Closed-form solutions for a Timoshenko’s beam on a semi-infinite plane subjected to a concentrated or distributed load were presented in which the Fourier transform is used. After the shear deformation was considered and a widened load distribution length on the centroid axis of the rail, which considered the load dispersion in an angle of 35°–40° from the top of the rail to the centroid axis, are adopted in the Fourier transform solution, the analytical results are in good agreement with finite element analysis. Formulas of equivalent bearing lengths for two types of rails used in China are recommended for practical use.

Validation of Nitinol SMA Characteristics Using Finite Element Analysis and Closed Form Solutions

2013 ◽  
Vol 856 ◽  
pp. 147-152
Author(s):  
S.H. Adarsh ◽  
U.S. Mallikarjun
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fe Analysis ◽  
Element Analysis ◽  
Complex Behaviour ◽  
Closed Form Solutions

Shape Memory Alloys (SMA) are promising materials for actuation in space applications, because of the relatively large deformations and forces that they offer. However, their complex behaviour and interaction of several physical domains (electrical, thermal and mechanical), the study of SMA behaviour is a challenging field. Present work aims at correlating the Finite Element (FE) analysis of SMA with closed form solutions and experimental data. Though sufficient literature is available on closed form solution of SMA, not much detail is available on the Finite element Analysis. In the present work an attempt is made for characterization of SMA through solving the governing equations by established closed form solution, and finally correlating FE results with these data. Extensive experiments were conducted on 0.3mm diameter NiTinol SMA wire at various temperatures and stress conditions and these results were compared with FE analysis conducted using MSC.Marc. A comparison of results from finite element analysis with the experimental data exhibits fairly good agreement.

An Improved Method for Designing Flexure-Based Nonlinear Springs

2012 ◽  
Author(s):  
Qiaoling Meng ◽  
Giovanni Berselli ◽  
Rocco Vertechy ◽  
Vincenzo Parenti Castelli
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Empirical Equations ◽  
Element Analysis ◽  
Closed Form Solutions ◽  
Nonlinear Springs ◽  
Aspect Ratios ◽  
Analytical Relations ◽  
Flexural Hinges

Monolithic Flexure-based Compliant Mechanisms (MFCM) can functionally act as nonlinear springs by providing a desired load-displacement profile at one point on their structure. Once the MFCM topology is chosen, these particular springs can be conveniently synthesized by resorting to the well-known Pseudo-Rigid-Body approximation, whose accuracy strongly depends on the modeling precision of the flexures’ principal compliance. For various types of flexures, closed-form solutions have been proposed which express the compliance factors as functions of the flexure dimensions. Nonetheless, the reliability of these analytical relations is limited to slender, beam-like, hinges undergoing small deflections. In order to overcome such limitations, this paper provides empirical equations, derived from finite element analysis, that can be used for the optimal design of circular, elliptical, and corner-filleted flexural hinges with general aspect ratios on the basis of both principal compliance and maximum bearable stress. As a case study, a nonlinear spring conceived as a four-bar linkage MFCM is synthesized and simulated by means of finite element analysis. Numerical results confirm that the aforementioned empirical equations outperform their analytical counterparts when modeling thick cross-section hinges undergoing large deflections.

Research and Applications of a Plane Embedded Combined Element Model Considering Bond and Slip

2013 ◽  
Vol 275-277 ◽  
pp. 1296-1301
Author(s):  
Ji Wei Wang ◽  
Qin Qin Qiao ◽  
Fei Leng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Deformation ◽  
Element Model ◽  
Beam Element ◽  
Shape Functions ◽  
Element Analysis ◽  
Bond Slip ◽  
Numerical Examples ◽  
Nodal Force

It is one of the most important issues for finite element analysis of lining structures that how to describe anchor rod reasonably and effectively and simulate the interaction between rod and concrete or rock. Virtual nodes are constructed in concrete/rock element at the ends of anchor rod and bond-slip element is set between virtual nodes and beam element which describes anchor rod. An embedded combined element with bond slip and shear deformation is established through the transformation of nodal force at nodes of bond-slip element to those of concrete/rock element via shape functions. The element is convenient for meshing element because the location and direction of anchor rod are not necessary to be considered. Meanwhile, the element has the advantage of low computing cost. Finally, the validity and efficiency are verified by numerical examples.

An Algorithm for Reducing the Size of Finite Element Closed-Form Source Code Files

2009 ◽  
Author(s):  
Sara McCaslin ◽  
Kent Lawrence
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Closed Form ◽  
Source Code ◽  
Simple Algorithm ◽  
Higher Order ◽  
Error Estimator ◽  
Element Analysis ◽  
Closed Form Solutions ◽  
Large Source

Closed-form solutions, as opposed to numerically integrated solutions, can now be obtained for many problems in engineering. In the area of finite element analysis, researchers have been able to demonstrate the efficiency of closed-form solutions when compared to numerical integration for elements such as straight-sided triangular [1] and tetrahedral elements [2, 3]. With higher order elements, however, the length of the resulting expressions is excessive. When these expressions are to be implemented in finite element applications as source code files, large source code files can be generated, resulting in line length/ line continuation limit issues with the compiler. This paper discusses a simple algorithm for the reduction of large source code files in which duplicate terms are replaced through the use of an adaptive dictionary. The importance of this algorithm lies in its ability to produce manageable source code files that can be used to improve efficiency in the element generation step of higher order finite element analysis. The algorithm is applied to Fortran files developed for the implementation of closed-form element stiffness and error estimator expressions for straight-sided tetrahedral finite elements through the fourth order. Reductions in individual source code file size by as much as 83% are demonstrated.

Finite Element Analysis of Blower Impeller Using Cyclic Symmetry

2007 ◽  
Vol 353-358 ◽  
pp. 1082-1085
Author(s):  
Chang Boo Kim ◽  
Young Chul Ahn ◽  
Bo Yeon Kim ◽  
Chong Du Cho ◽  
Hyeon Gyu Beom
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fourier Transform ◽  
Natural Vibration ◽  
Cyclic Symmetry ◽  
Static Characteristics ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Non Linear ◽  
Comparison Of The Results

In this paper, we present an efficient method for conducting a finite element analysis of a structure with cyclic symmetry and apply the method to analyze the natural vibration and linear and non-linear static characteristics of a blower impeller. A blower impeller is composed of circumferentially repeated substructures. The whole structure is partitioned into substructures, and the finite element analysis can thus be performed with one representative substructure by using the transformed equations for each number of nodal diameters, which are derived from a discrete Fourier transform. We calculated the natural vibration and linear and non-linear static characteristics of a blower impeller without a stiffening ring, and with small as well as large stiffening rings, respectively. The accuracy and efficiency of the presented method are verified by comparison of the results obtained from the analysis using a substructure to those obtained using the whole structure.

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