A Finite-Element Solution of Thermal Distortion with Applications to Thrust Bearings

1984 ◽  
Vol 28 (04) ◽  
pp. 282-289
Author(s):  
James H. Ma
Keyword(s):  
Finite Element ◽  
Hot Spot ◽  
Mesh Size ◽  
Computer Code ◽  
Development Project ◽  
Element Space ◽  
Element Mesh ◽  
Data Set ◽  
Mechanical Responses ◽  
Nonlinear Temperature

A finite-element code to account for thermal expansion in a solid was developed for the Independent Research and Independent Exploratory Development project "Tribology of Sliding Surface Bearings." The program is based on a two-dimensional model using a second or higher-order interpolation function in the element space that will allow a diverse temperature field, such as a steep nonlinear temperature gradient, to be prescribed in a solid body. The computer code has a definite advantage over certain finite-element systems that are commercially available. Many accept only a constant, or averaged, temperature input into their element space. With the new capabilities, complex thermal mechanical responses under severe temperature gradients can be readily analyzed. For instance, the hot spot in a ship's landing deck due to the concentrated heat load, such as those generated by high-temperature jet exhaust, can be more realistically represented by the elements of current development. The element mesh size and the input data set are more manageable.

scholarly journals Influence of finite element mesh size on the carrying capacity analysis of single-row ball slewing bearing

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Peiyu He ◽  
Qinrong Qian ◽  
Yun Wang ◽  
Hong Liu ◽  
Erkuo Guo ◽  
...  
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Mesh Size ◽  
Finite Element Mesh ◽  
Fe Model ◽  
Element Mesh ◽  
Heavy Load ◽  
Slewing Bearing ◽  
Maximum Contact ◽  
Slewing Bearings

Slewing bearings are widely used in industry to provide rotary support and carry heavy load. The load-carrying capacity is one of the most important features of a slewing bearing, and needs to be calculated cautiously. This paper investigates the effect of mesh size on the finite element (FE) analysis of the carrying capacity of slewing bearings. A local finite element contact model of the slewing bearing is firstly established, and verified using Hertz contact theory. The optimal mesh size of finite element model under specified loads is determined by analyzing the maximum contact stress and the contact area. The overall FE model of the slewing bearing is established and strain tests were performed to verify the FE results. The effect of mesh size on the carrying capacity of the slewing bearing is investigated by analyzing the maximum contact load, deformation, and load distribution. This study of finite element mesh size verification provides an important guidance for the accuracy and efficiency of carrying capacity of slewing bearings.

Validation of Computer Models for Nuclear Material Shipping Packages

2007 ◽  
Author(s):  
Narendra K. Gupta ◽  
Eugene P. Shine ◽  
Richard C. Tuckfield ◽  
Jeffrey T. Fong
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Computer Model ◽  
Thermal Response ◽  
Mesh Size ◽  
Computer Code ◽  
Computer Models ◽  
Physical Reality ◽  
Nuclear Material ◽  
Convergence Criteria

Computer models are abstractions of physical reality and are routinely used for solving practical engineering problems. These models are prepared using large complex computer codes that are widely used in the industry. Patran/Thermal is such a finite element computer code that is used for solving complex heat transfer problems in the industry. Finite element models of complex problems involve making assumptions and simplifications that depend upon the complexity of the problem and upon the judgment of the analysts. The assumptions involve mesh size, solution methods, convergence criteria, material properties, boundary conditions, etc. that could vary from analyst to analyst. All of these assumptions are, in fact, candidates for a purposeful and intended effort to systematically vary each in connection with the others to determine there relative importance or expected overall effect on the modeled outcome. These kinds of models derive from the methods of statistical science and are based on the principles of experimental designs. These, as all computer models, must be validated to make sure that the output from such an abstraction represents reality [1,2]. A new nuclear material packaging design, called 9977, which is undergoing a certification design review, is used to assess the capability of the Patran/Thermal computer model to simulate 9977 thermal response. The computer model for the 9977 package is validated by comparing its output with the test data collected from an actual thermal test performed on a full size 9977 package. Inferences are drawn by performing statistical analyses on the residuals (test data – model predictions).

scholarly journals Finite Element Analysis of Bearing Capacity of Reinforced Concrete Pipe Strengthened by TRC

2021 ◽  
Vol 261 ◽  
pp. 02044
Author(s):  
Xinming Zhao ◽  
Cheng Kan ◽  
Yuxiao Ye ◽  
Shaowei Hu ◽  
Baibing Zhou
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Mesh Size ◽  
Element Model ◽  
Displacement Curve ◽  
Concrete Element ◽  
Element Analysis ◽  
Element Mesh ◽  
Concrete Pipe ◽  
Load Simulation

A non-linear 3D finite element model was established to simulate the three edge-bearing test of TRC reinforced concrete pipe. The pipe load-displacement curve, cracking load, and ultimate load simulation values are in good agreement with the test values. Subsequently, a parametric study was conducted. The effects of reinforcement layer bonding mode, mesh size of concrete element, mesh distribution rate and concrete compressive strength on the performance of reinforced concrete pipeline strengthened by TRC were considered. It provides a basis for the design of TRC reinforced concrete pipes.

scholarly journals Numerical and Experimental Investigations on a Three-Dimensional Rod-Plate Impact

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Jianyao Wang ◽  
Zhuyong Liu ◽  
Jiazhen Hong
Keyword(s):  
Finite Element ◽  
Rigid Motion ◽  
Mesh Size ◽  
Numerical Approach ◽  
Numerical Results ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Element Mesh ◽  
Simulation Accuracy ◽  
Oblique Impacts

There are a few numerical simulation methods available for impact problems. However, most numerical results are not validated experimentally. The goal of this paper is to examine how well the simulation results correspond to the physical reality. In this work, normal and oblique impacts of a hemispherical-tip rod on a square plate are investigated both numerically and experimentally. In the numerical approach, finite element method is used to discretize the contact bodies to describe the deformation precisely combined with the floating reference frame method to describe the rigid motion. In the experimental study, strain gauges and Laser Doppler Vibrometers are employed to measure the high-frequency impact responses. Detailed comparative studies between numerical and experimental results are performed. In the case of normal impact, great attention is given to investigate the influence of finite element mesh size on the simulation accuracy and a “Prediction-Refinement” discretization strategy is proposed for obtaining a mesh which is optimal for impact dynamics. In the case of oblique impact, the influence of Coulomb’s friction coefficient is investigated additionally. It shows that the numerical results are in good agreement with the experimental results for both normal and oblique impacts.

scholarly journals An Analysis Method of Carrying Capacity Accuracy of Three-Row Roller Slewing Bearing

Mechanika ◽  
2021 ◽  
Vol 27 (5) ◽  
pp. 360-367
Author(s):  
Peiyu HE ◽  
Yun WANG ◽  
Hua WANG
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Carrying Capacity ◽  
Large Scale ◽  
Mesh Size ◽  
Element Model ◽  
Element Mesh ◽  
Slewing Bearing ◽  
Core Components ◽  
Heavy Loads

Three-row roller slewing bearings are the core components of large-scale rotating equipment. It has a large structural size and is subjected to heavy loads, which requires extremely high carrying capacity. The effect of finite element mesh size on the carrying capacity accuracy of three-row roller slewing bearing is investigated. A local finite element model is established to analyze the contact area between the roller and the raceway, which is compared with the Hertz contact theory to verify the reasonable mesh size of the finite element model. The local spring finite element model is established, and the effect of the mesh size on the offset and the declination of the upper and lower raceway is investigated; The overall finite element model of the slewing bearing is established to analyze the effect of the mesh size and the nonlinear spring stiffness on the carrying capacity accuracy. The whole circle deformation of the ring and the load distribution is investigated to determine the reasonable mesh size. This article provides a method and idea for the verification of the three-row roller slewing bearing finite element model, which is beneficial to improve the calculation accuracy of the bearing capacity of the three-row roller slewing bearing.

scholarly journals A family of C1 quadrilateral finite elements

2021 ◽  
Vol 47 (6) ◽  
Author(s):  
Mario Kapl ◽  
Giancarlo Sangalli ◽  
Thomas Takacs
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Degrees Of Freedom ◽  
Approximation Error ◽  
Mesh Size ◽  
Element Space ◽  
Quadrilateral Elements ◽  
Macro Element ◽  
Quadrilateral Finite Element ◽  
Better Than

AbstractWe present a novel family of C1 quadrilateral finite elements, which define global C1 spaces over a general quadrilateral mesh with vertices of arbitrary valency. The elements extend the construction by Brenner and Sung (J. Sci. Comput. 22(1-3), 83-118, 2005), which is based on polynomial elements of tensor-product degree p ≥ 6, to all degrees p ≥ 3. The proposed C1 quadrilateral is based upon the construction of multi-patch C1 isogeometric spaces developed in Kapl et al. (Comput. Aided Geometr. Des. 69, 55–75 2019). The quadrilateral elements possess similar degrees of freedom as the classical Argyris triangles, developed in Argyris et al. (Aeronaut. J. 72(692), 701–709 1968). Just as for the Argyris triangle, we additionally impose C2 continuity at the vertices. In contrast to Kapl et al. (Comput. Aided Geometr. Des. 69, 55–75 2019), in this paper, we concentrate on quadrilateral finite elements, which significantly simplifies the construction. We present macro-element constructions, extending the elements in Brenner and Sung (J. Sci. Comput. 22(1–3), 83–118 2005), for polynomial degrees p = 3 and p = 4 by employing a splitting into 3 × 3 or 2 × 2 polynomial pieces, respectively. We moreover provide approximation error bounds in $L^{\infty }$ L ∞ , L2, H1 and H2 for the piecewise-polynomial macro-element constructions of degree p ∈{3,4} and polynomial elements of degree p ≥ 5. Since the elements locally reproduce polynomials of total degree p, the approximation orders are optimal with respect to the mesh size. Note that the proposed construction combines the possibility for spline refinement (equivalent to a regular splitting of quadrilateral finite elements) as in Kapl et al. (Comput. Aided Geometr. Des. 69, 55–75 30) with the purely local description of the finite element space and basis as in Brenner and Sung (J. Sci. Comput. 22(1–3), 83–118 2005). In addition, we describe the construction of a simple, local basis and give for p ∈{3,4,5} explicit formulas for the Bézier or B-spline coefficients of the basis functions. Numerical experiments by solving the biharmonic equation demonstrate the potential of the proposed C1 quadrilateral finite element for the numerical analysis of fourth order problems, also indicating that (for p = 5) the proposed element performs comparable or in general even better than the Argyris triangle with respect to the number of degrees of freedom.

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