A Unified Analytical Method of Stress Analysis for Tubesheet—Part II: Case Study

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Hongsong Zhu
Keyword(s):  
Stress Analysis ◽  
Analytical Method ◽  
Heat Exchangers ◽  
Numerical Comparison ◽  
Element Analysis ◽  
Comparison Results ◽  
Different Types ◽  
The Unified Method ◽  
Unified Method

Based on the unified analytical method of stress analysis for fixed tubesheet (TS) heat exchangers (HEX), floating head and U-tube HEX presented in Part I, numerical comparisons with ASME method are performed in this paper as Part II. Numerical comparison results indicate that predictions given by the unified method agree well with finite element analysis (FEA), while ASME results are not accurate or not correct. Therefore, it is concluded that the unified method deals with thin TS of different types of HEX in equal detail with confidence to predict design stresses.

The Unified Theory of Tubesheet Design - Part III: Comparison with ASME Method and Case Study

2021 ◽  
Author(s):  
Hong-Song Zhu ◽  
Jinguo Zhai ◽  
Guo-Yan Zhou
Keyword(s):  
Heat Exchangers ◽  
Numerical Comparison ◽  
Unified Theory ◽  
Element Analysis ◽  
Theoretical Comparison ◽  
Comparison Results ◽  
Different Types ◽  
Special Case ◽  
Simplified Mechanical Model

Abstract Based on the unified theory of tubesheet (TS) design for fixed TS heat exchangers (HEX), floating head and U-tube HEX presented in Part I and Part II, theoretical and numerical comparisons with ASME method are performed in this paper as Part III. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the unified theory. Numerical Comparison results indicate that predictions given by the unified theory agree well with finite element analysis (FEA), while ASME results are not accurate or not correct. Therefore, it is concluded that the unified theory deals with different types of HEX in equal detail with confidence to predict design stresses.

A Unified Analytical Method of Stress Analysis for Tubesheet—Part I: Theoretical Foundation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Hongsong Zhu
Keyword(s):  
Stress Analysis ◽  
Analytical Method ◽  
Numerical Comparison ◽  
Design Standards ◽  
Element Analysis ◽  
Technical Literature ◽  
Edge Conditions ◽  
The Unified Method ◽  
Special Case ◽  
Unified Method

Based on a brief review of existing tubesheet (TS) design standards and the pertinent technical literature, a unified analytical method of stress analysis for fixed TS heat exchangers (HEXs), floating head and U-tube HEXs is proposed by removing the midplane symmetry (MPS) assumption, which assumes a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the HEX or one TS needs be considered. The unified method can be successfully extended to the situations for different TS materials, unequal TS thicknesses, different TS edge conditions, different TS temperatures, pressures drop and dead weights on two TSs. The effects of pressure in TS perforations and temperature gradient in TS thickness direction are also considered by the unified method. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the unified method. Numerical comparison indicates that predictions given by the unified method agree well with finite element analysis (FEA), while ASME results are not accurate or not correct.

Refined General Theory of Stress Analysis for Tubesheet

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Hongsong Zhu
Keyword(s):  
General Theory ◽  
Stress Analysis ◽  
Heat Exchangers ◽  
Numerical Comparison ◽  
Refined Theory ◽  
Element Analysis ◽  
Comparison Results ◽  
Special Cases ◽  
Edge Conditions ◽  
Plate On Elastic Foundation

The stress analysis method for fixed tubesheet (TS) heat exchangers (HEX) in pressure vessel codes such as ASME VIII-1, EN13445, and GB151 is based on the classical theory of thin plate on elastic foundation. In addition, these codes all assume a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the unit or one TS is needed to be considered. In this study, a refined general theory of stress analysis for TS is presented which also considers unequal thickness for two TSs, different edge conditions, pressure drop and deadweight on two TSs, the anisotropic behavior of the TS in thickness direction, and transverse shear deformation in TS. Analysis shows floating and U-tube heat exchangers are the two special cases of the refined theory. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the refined theory. Numerical comparison results indicate that predictions given by the refined theory agree well with finite element analysis (FEA) for both thin and thick TS heat exchangers, while ASME results are not accurate or not correct. Therefore, it is concluded that the presented refined general theory provides a single unified method, dealing with both thin and thick TSs for different type (U type, floating, and fixed) HEXs in equal detail, with confidence to predict design stresses.

scholarly journals Stress Analysis and Design of Main Reducer Housing Using Finite Element Method

2018 ◽  
Vol 221 ◽  
pp. 04008
Author(s):  
S. Wang
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Numerical Comparison ◽  
Original Design ◽  
Element Analysis ◽  
Time Saving ◽  
Analysis And Design ◽  
Analysis Process ◽  
Comparison Results ◽  
Strength And Stiffness

The main reducer housing takes over the shaft loads from gear engagement and transmits to other components, such as differential, semiaxle and driving wheels, so the main reducer housing with enough strength and stiffness is very important. Some factors preventing it from failure need to be taken into consideration when design it. To design a main reducer housing with better performance, in this paper, FEA (Finite Element Analysis) is used to analysis the main reducer housing and to find out some big stress regions. Then, some modifications are proposed to eliminate those big stress regions and obtain a reliable main reducer housing. During the analysis process, an annulus model is built and the reaction forces between the differential bearing seats and axle housing are calculated to determine whether they contact with each other. Finally, some design methods and improvements of the original design main reducer housing are proposed. And numerical comparison results of the stress distribution of the original and improved main reducer housing validate the effectiveness of the proposed methods and modifications in this paper. Those stress analysis and modifications in this paper are time-saving and money-saving before mass production.

The Stress Analysis of Heat Exchanger Expansion Joints in the Elastic Range

1973 ◽  
Vol 95 (1) ◽  
pp. 145-150 ◽  
Author(s):  
L. J. Wolf ◽  
R. M. Mains
Keyword(s):  
Heat Exchanger ◽  
Stress Analysis ◽  
Strain Gage ◽  
Analytical Method ◽  
Heat Exchangers ◽  
Expansion Joints ◽  
Elastic Range ◽  
Shell And Tube ◽  
Strain Gage Tests

Expansion joints of the style most commonly used in shell and tube heat exchangers were studied analytically and experimentally in the elastic range. A method of computing stresses and deformations for pressure and expansion loadings is demonstrated. Strain-gage tests show the analytical method to be accurate.

The Analytical Modeling and Finite Element Analysis of a Bridge-Type Displacement Amplifier

2013 ◽  
Vol 397-400 ◽  
pp. 652-655
Author(s):  
Chuan Liang Shen ◽  
Jing Shi Dong ◽  
Feng Jun Tian
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Analytical Method ◽  
Analytical Relationship ◽  
Link Length ◽  
Element Analysis ◽  
Amplification Ratio ◽  
Comparison Results ◽  
Bridge Type ◽  
Element Method

The bridge-type displacement amplifier is modeled by the analytical method and finite element method. The analytical relationship between the input displacement and output displacement is established. The analytical model is validated by finite element method. The geometric parameters influence of amplification ratio is studied. The comparison results show that the link length and the link angle influence the amplification ratio dramatically. A small link angle and a large link length is beneficial to the amplification ratio. The finite element method has a more precise simulation results than the analytical method under the circumstance of small link angle and short link length.

scholarly journals Analysis of Expansion Joint - A Case Study

2021 ◽  
Vol 9 (10) ◽  
pp. 45-51
Author(s):  
Prof. P R Subramaniam
Keyword(s):  
Variable Pressure ◽  
Pressure Loading ◽  
Ansys Software ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Pressure Load ◽  
Different Types ◽  
Comprehensive Modeling ◽  
Metallic Bellow

Abstract: Automotive, Aerospace, Pipeline industries widely use Bellows. Different types of bellows are used in these industries. The bellows are used for contraction or expansion applications. Repeated variable pressure loading and displacement on Metallic bellows joints results in bellows failure. This paper is a comprehensive modeling and analysis of an axial type exhaust metallic bellow due to varying pressure load and circumferential and radial displacement. All analysis completed using ANSYS software considering variable pressure load and cylindrical displacement as a boundary condition and perused the consequences. Stress distribution in the conditions of Case (i) variable pressure load and Case (ii) displacement are obtained. Keywords: ANSYS, FE Bellows, Finite Element Analysis, Bellow Failures

Analysis and Calculation of Strength and Stiffness for Flexible Shell Element of Corner-Corner Type in Fixed Tubesheet Heat Exchangers

2021 ◽  
Author(s):  
Guodong Zhu ◽  
Feng Xu ◽  
Guoshan Xie ◽  
Jie Shen
Keyword(s):  
Analytical Method ◽  
Heat Exchangers ◽  
Large Diameter ◽  
Outer Cylinder ◽  
Shell Element ◽  
Axial Stiffness ◽  
Flexible Shell ◽  
Element Analysis ◽  
Expansion Joints ◽  
Local Stresses

Abstract The flexible shells of corner-corner type are often utilized as distribution, vapor belts to distribute medium or expansion joints to compensate the difference of displacement between shell side and tube side due to temperature or pressure in heat exchangers. Corner-corner type can be fabricated for large diameter equipment because of better manufacturing process and space saving. However, at present, the design depends on experience and the primary stress of the outer cylinder. The lack of accurate and integral calculation methods have limited its application and even resulted in safety hazard. In this paper, a mechanical model is established for the flexible shell of corner-corner type and analytical solution including the global stresses, local stresses, stress trend curves and axial stiffness is proposed based on the plate and shell theory. The analytical method is verified by finite element analysis. It is demonstrated that the analytical method is accurate and reliable. It is pointed out that the local stresses of each element should not be ignored. Meanwhile, the stresses may transfer to reverse value along the path away from the maximum stress, which would arise the buckling failure.

Finite Element Analysis and Experimental Investigation of Tubesheet Structure

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
C. F. Qian ◽  
H. J. Yu ◽  
L. Yao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Heat Exchangers ◽  
Thermal Load ◽  
Axial Strain ◽  
Element Analysis ◽  
Shell Elements ◽  
Different Types ◽  
Analysis Models

In order to investigate the possibility of numerical simulation for whole structures of heat exchangers, two finite element analysis models have been established for the fixed tubesheet structure composed of tubesheet, cylindrical shell, and tubes using different types of elements. Stresses and deformations produced by pressure load or thermal load are calculated, and the axial strain at the middle area of the cylindrical shell is experimentally measured. By comparing the numerical results with experimental measurements, it is found that both finite element analysis models can give satisfactory results. Considering the difficulties in modeling heat exchangers, beam and shell elements are recommended.

scholarly journals Research on influence of mesh parameters modification on solution accuracy of finite element analysis

2021 ◽  
Vol 1199 (1) ◽  
pp. 012008
Author(s):  
M Handrik ◽  
J Majko ◽  
M Vaško ◽  
F Dorčiak ◽  
P Kopas
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Accurate Result ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Different Types ◽  
Linear Elements ◽  
Solution Accuracy

Abstract The paper deals with the solution accuracy of the stress in the structure using the finite element analysis. In general, hexahedron elements are more accurate than tetrahedron elements and quadratic elements are more accurate than linear elements. The primary aim of the article is to perform comparison of the obtained results and calculation parameters (such as time and so on) for different types of elements and the elements size. Usage less accurate elements like linear tetrahedron under certain circumstances could lead to sufficiently accurate result of stress analysis.

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