A Proposed General Method of Stress Analysis for Tubesheet of Heat Exchanger

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Hongsong Zhu ◽  
Jinguo Zhai ◽  
Haifeng Wang ◽  
Yixiang Zheng
Keyword(s):  
Stress Analysis ◽  
Method Comparison ◽  
Dead Weight ◽  
Element Analysis ◽  
Plate And Shell ◽  
Comparison Results ◽  
Special Cases ◽  
Edge Conditions ◽  
Special Case ◽  
General Method

The stress analysis method for fixed tubesheet (TS) heat exchangers (HEX) in pressure vessel codes such as ASME VIII-1, EN13445, and GB151 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 need to be considered. In this study, the midplane symmetry assumption is discarded. More common situations are considered such as unequal TS thickness, different edge conditions, pressure drop, and dead weight on two TSs. Based on the classical thin plate and shell theoretical solution, an analytical method of stress analysis for TS is presented. The proposed method is suitable for different types of HEX due to fewer assumptions employed in this study. Analysis shows that floating and U-tube HEX are the two special cases of the proposed method. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the proposed method. Typical geometries and loading are considered, and the proposed method is used to check the adequacy of design. Predictions are compared with the results obtained from axisymmetric finite element analysis (FEA) and current ASME method. Comparison results indicate that predictions given by this paper agree well with FEA while ASME results are not correct or not accurate.

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.

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.

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.

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.

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.

Stress Analysis of Functionally Graded Cylinders Subjected to Thermo-Mechanical Loads Based on Bernstein Polynomials

2010 ◽  
Author(s):  
Ali Fallah ◽  
Mohammad Mohammadi Aghdam ◽  
Abdolreza Pasharavesh
Keyword(s):  
Stress Analysis ◽  
Bernstein Polynomials ◽  
Method Comparison ◽  
Pressure Vessels ◽  
Functionally Graded ◽  
Radial Coordinate ◽  
Governing Equations ◽  
Mechanical Loads ◽  
Analytical Results ◽  
Special Cases

Stress analysis of thick walled functionally graded (FG) cylindrical pressure vessels subjected to uniform axisymmetric thermo-mechanical loads is presented using Bernstein polynomials. All thermal and mechanical properties except Poisson’s ratio of the FG vessels vary through the thickness with arbitrary functions of the radial coordinate. Based on the thermo-elasticity theory, the first law of thermodynamics and axisymmetric assumption, the governing equations of the semi-coupled thermo-elasticity problem reduce to a set of second order boundary value problem. Galerkin method together with Bernstein polynomials is used to obtain solution for the governing equations. The presented method is simple to implement, efficient and accurate. Predictions of some special cases for which analytical results are available in the literature are used to validate the method. Comparison of the results for stress and displacement components and temperature distribution with analytical results shows excellent agreement. Furthermore, predictions for radial displacement, stresses and temperature in various cylindrical pressure vessels with different material models are presented for future references.

Finite Element Analysis of Drum on the New Type Self-Driven Towing Machine for Cable

2011 ◽  
Vol 55-57 ◽  
pp. 664-669
Author(s):  
Jin Ning Nie ◽  
Hui Wang ◽  
De Feng Xie
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Compressive Stress ◽  
Wire Rope ◽  
Ansys Software ◽  
Element Analysis ◽  
Structure Improvement ◽  
Improvement Measures ◽  
New Type

According to the situation that the dual-friction drums on the new type towing machine lack stress analysis when designed, the safety is difficult to test and verify. The pull of wire rope in various positions was derived and calculated, so both compressive stress and tangent friction force generated by the pull of wire rope were calculated. The result made by ANSYS software demonstrates the safety of the left drum which suffers from larger loads, structure improvement measures are put forward for the drum.

Stress Analysis and Structure Optimization for the Opening Flat Cover of Pressure Vessels

2012 ◽  
Vol 538-541 ◽  
pp. 3253-3258 ◽  
Author(s):  
Jun Jian Xiao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Analysis ◽  
Structure Optimization ◽  
Pressure Vessels ◽  
Secondary Stress ◽  
Element Analysis ◽  
Primary Stress ◽  
Flat Cover

According to the results of finite element analysis (FEA), when the diameter of opening of the flat cover is no more than 0.5D (d≤0.5D), there is obvious stress concentration at the edge of opening, but only existed within the region of 2d. Increasing the thickness of flat covers could not relieve the stress concentration at the edge of opening. It is recommended that reinforcing element being installed within the region of 2d should be used. When the diameter of openings is larger than 0.5D (d>0.5D), conical or round angle transitions could be employed at connecting location, with which the edge stress decreased remarkably. However, the primary stress plus the secondary stress would be valued by 3[σ].

Bending of Thin Ring-Sector Plates

1951 ◽  
Vol 18 (4) ◽  
pp. 359-363
Author(s):  
L. I. Deverall ◽  
C. J. Thorne
Keyword(s):  
Continuous Function ◽  
Bending Moment ◽  
Circular Ring ◽  
Circular Plates ◽  
Thin Ring ◽  
Special Cases ◽  
Edge Conditions

Abstract General expressions for the deflection of plates whose planform is a sector of a circular ring are given for cases in which the straight edges have arbitrary but given deflection and bending moment. The solutions are given for all combinations of physically important edge conditions on the two circular edges. Sectors of circular plates are included as special cases. Solutions are given for a general load which is a continuous function of r, and a sectionally continuous function of θ, where r and θ are the usual polar co-ordinates with the pole at the center of the ring. Several specific examples are given.

Strength-based design of a sunflower stalk cutter machine design using finite element analysis and experimental validation

2021 ◽  
pp. 095440622110597
Author(s):  
Gürkan İrsel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Strain Gage ◽  
Experimental Validation ◽  
Experimental Studies ◽  
Fatigue Analysis ◽  
Structural Stress ◽  
Element Analysis ◽  
Strength Based

In this study, the total algorithm of the strength-based design of the system for mass production has been developed. The proposed algorithm, which includes numerical, analytical, and experimental studies, was implemented through a case study on the strength-based structural design and fatigue analysis of a tractor-mounted sunflower stalk cutting machine (SSCM). The proposed algorithm consists of a systematic engineering approach, material selection and testing, design of the mass criteria suitability, structural stress analysis, computer-aided engineering (CAE), prototype production, experimental validation studies, fatigue calculation based on an FE model and experimental studies (CAE-based fatigue analysis), and an optimization process aimed at minimum weight. Approximately 85% of the system was designed using standard commercially available cross-section beams and elements using the proposed algorithm. The prototype was produced, and an HBM data acquisition system was used to collect the strain gage output. The prototype produced was successful in terms of functionality. Two- and three-dimensional mixed models were used in the structural analysis solution. The structural stress analysis and experimental results with a strain gage were 94.48% compatible in this study. It was determined using nCode DesignLife software that fatigue damage did not occur in the system using the finite element analysis (FEA) and experimental data. The SSCM design adopted a multi-objective genetic algorithm (MOGA) methodology for optimization with ANSYS. With the optimization solved from 422 iterations, a maximum stress value of 57.65 MPa was determined, and a 97.72 kg material was saved compared to the prototype. This study provides a useful methodology for experimental and advanced CAE techniques, especially for further study on complex stress, strain, and fatigue analysis of new systematic designs desired to have an optimum weight to strength ratio.

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