scholarly journals An efficient optimization method for structures with local non-linearity

2016 ◽  
Vol 20 (suppl. 3) ◽  
pp. 879-886
Author(s):  
Zhao-Li Zheng ◽  
Yu-Qi Wang ◽  
Di Zhang
Keyword(s):  
Turbine Blade ◽  
Degrees Of Freedom ◽  
Fractal Theory ◽  
Linear Part ◽  
Equivalent Stress ◽  
Iteration Process ◽  
Optimization Method ◽  
Contact Model ◽  
Maximum Equivalent Stress ◽  
The Common

During the operation of turbines, one of the common accidents is due to the structure failure of blades. The contact model with strong non-linearity and time variation makes it difficult to be analyzed. In this paper, firstly, the contact model is described by using fractal theory. Secondly, the new method for the optimization of turbine blade is proposed, which is a kind of structure with local nonlinearity and multi degree of freedom. The method reduces the number of degrees of freedom by forming a new super element, which makes the linear part of turbine blade without repeated calculation in the non-linear iteration process. Therefore, it can shorten the calculation time and reduce the demand for computing resources. Finally, an optimization of the turbine blade is carried out, and the maximum equivalent stress reduces by 13.19%, which proves the effectiveness of the new optimization method.

Design Optimization for Fir-Tree Root of Turbine Blade Considering Manufacturing Variations

2013 ◽  
Vol 694-697 ◽  
pp. 2733-2737
Author(s):  
Qin Zhou ◽  
Ming Hui Zhang ◽  
Hui Yong Chen ◽  
Yong Hui Xie
Keyword(s):  
Particle Swarm Optimization ◽  
Turbine Blade ◽  
Equivalent Stress ◽  
Particle Swarm ◽  
Pattern Search ◽  
Design System ◽  
Contact Method ◽  
Swarm Optimization ◽  
Maximum Equivalent Stress ◽  
Manufacturing Variation

An optimization design system for fir-tree root of turbine blade has been developed in this paper. In the system, a parametric model of the blade and rim was established based on the parametric design language APDL, and nonlinear contact method was used for analysis by ANSYS, meanwhile some optimization algorithms, such as Pattern Search Algorithm, Genetic Algorithm, Simulated Annealing Algorithm and Particle Swarm Optimization, were adopted to control the optimizing process. Five cases of manufacturing variation in contact surfaces between root and rim were taken into account, and the design objective was to minimize the maximum equivalent stress of root-rim by optimizing eight critical geometrical dimensions of the root and rim. As a result, the maximum equivalent stress of root-rim decreases markedly after the optimization in all cases. In consideration of both precision and computing time, particle swarm optimization is assessed as the best algorithm to solve structure optimization problem in this work. Corresponding to five different cases of manufacturing variation, the maximum equivalent stress of root and rim reduces by 7%, 8%; 27%, 24%; 27%, 22%; 25%, 19%; 10%, 14% using the Particle Swarm Optimization.

Design Optimization for Double-T Root and Rim of Turbine Blade with Three-Dimensional Finite Element Method

2012 ◽  
Vol 215-216 ◽  
pp. 239-243
Author(s):  
Ming Hui Zhang ◽  
Di Zhang ◽  
Yong Hui Xie
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Design Optimization ◽  
Turbine Blade ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Maximum Equivalent Stress ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Element Method

As the main bearing part in a turbine blade, the root carries most of the loads of the whole blade. The improvement of the root structure can be used to enhance the operation reliability of steam turbine. The research on design optimization for double-T root and rim of a turbine blade was conducted by three-dimensional finite element method. Based on the APDL (ANSYS parametric design language), a multi-variable parametric model of the double-T root and rim was established. Twelve characteristic geometrical variables of the root-rim were optimized to minimize the maximum equivalent stress. The optimal structure of the double-T root-rim is obtained through the optimization. Compared with the original structure, the equivalent stress level of the root and rim has a significant reduction. Specifically, the maximum equivalent stress of root and rim reduces by 14.25% and 13.59%, respectively.

Research on Three-Dimensional Structure Optimization for Fir-Tree Root and Rim of Turbine Blade with Complex Damping Structure

2013 ◽  
Vol 312 ◽  
pp. 55-59
Author(s):  
Ming Hui Zhang ◽  
Qiang Zhang ◽  
Lu Zheng ◽  
Di Zhang
Keyword(s):  
Turbine Blade ◽  
Equivalent Stress ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Mathematical Optimization ◽  
Structure Optimization ◽  
Dimensional Structure ◽  
Initial Structure ◽  
Maximum Equivalent Stress ◽  
Complex Damping

The research on structure optimization for the fir-tree root and rim of a steam turbine blade with complex damping structure was conducted by three-dimensional contact finite element method and mathematical optimization algorithm. A multi-variable parametric model of three turbine blades and rims with fir-tree root and rim was established. Twelve critical geometrical variables of the root-rim were optimized to minimize the maximum equivalent stress of the root-rim. The optimal structure of the fir-tree root-rim was finally obtained through the optimization process and the equivalent stress of the root and rim both had evident reductions, Compared with the initial structure, the maximum equivalent stress of the root and rim reduced by 13.47% and 12.26%, respectively. Relevant work is expected to support the design of turbine blade root-rim in theory and improve the operation reliability of turbo-machinery to some extent.

Finite Element Analysis and Multidisciplinary Design Optimization of Diesel Engine Connecting Rod Based on ISIGHT

2012 ◽  
Vol 479-481 ◽  
pp. 1863-1867
Author(s):  
Shou Guang Yao ◽  
Sheng Chen Zhao ◽  
Fei Liu
Keyword(s):  
Diesel Engine ◽  
Design Optimization ◽  
Multidisciplinary Design Optimization ◽  
Design Method ◽  
Equivalent Stress ◽  
Optimization Method ◽  
Multidisciplinary Design ◽  
Connecting Rod ◽  
Element Analysis ◽  
Maximum Equivalent Stress

Based on the multidisciplinary design optimization method and the MDO software ISIGHT, the 16PA6STC diesel engine connecting rod was taken to the model, used the Pro/engineer software to build the 3D model of connecting rod. The software ANSYS and Nastran was taken to complete the static analysis and modal analysis to get the maximum equivalent stress and the first and second modal frequencies. the software including Pro/Engineer、ANSYS、Nastran, was combined on the ISIGHT to complete the structural optimization work on the condition of restrain the stress and modal of the connecting rod, to explore the application of the MDO design method in the diesel engine connecting rod structure optimization field, offer a reference for the further improvement design study.

scholarly journals Optimal design and experiment study of the double spherical rotor of the MSCSG

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042199848
Author(s):  
Weijie Wang ◽  
Xiaocen Chen ◽  
Qiang Liu ◽  
Yahong Fan
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Control Function ◽  
Dynamic Balance ◽  
Equivalent Stress ◽  
Mechanical Analysis ◽  
Magnetic Bearing ◽  
Maximum Equivalent Stress ◽  
And Control ◽  
Measurement And Control

The magnetically suspended control and sense gyroscope (MSCSG) integrates spacecraft attitude measurement and control function; this paper proposes a double spherical rotor (DSR) for MSCSG. The DSR realizes the five degrees of freedom (DOFs) full active control and full channel magnetic path decoupling by the following design: the spherical axial/radial reluctance magnetic bearings are adopted to control the 3DOFs translation of rotor in the range of double spherical envelope, Lorentz force magnetic bearing (LFMB) is used to precisely drive the 2DOFs universal deflection of rotor. The optimization model is established based on the structural mechanical analysis, taking the deviation between rotor centroid and shape center as the optimization objective, choosing the first order resonance frequency, maximum equivalent stress, rigid body displacement, polar moment of inertia and inertia ratio as constraints. Then the DSR is optimized and simulated by the finite element, the MSCSG principle prototype based on DSR is successfully developed, the online dynamic balance experiment and modal test of the DSR are conducted, where the vibration amount of the DSR decreases from 20 μm before the experiment to 0.14 μm after the experiment, which decreases by 99.3%, the first test modal is 2881 Hz which is 5% different from the finite element simulation value of 3034 Hz. The results show that the DSR has the good mechanical properties and magnetic circuit decoupling characteristics.

Study on Optimization and FEM Analysis of Centrifugal Pump Body Structure

2010 ◽  
Vol 154-155 ◽  
pp. 1744-1747
Author(s):  
Lan Ying Wu ◽  
Yan Lin Wang
Keyword(s):  
Centrifugal Pump ◽  
Cell Size ◽  
Equivalent Stress ◽  
Grid Cell ◽  
Fem Analysis ◽  
Mechanical Equipment ◽  
Body Structure ◽  
Performance Requirements ◽  
Maximum Equivalent Stress ◽  
The Common

The centrifugal pump is the common mechanical equipment, which is extensively applied in the water conservancy, ships and other projects. In this paper, the centrifugal pump body structure was analyzed based on the actual working conditions, and the structure was also optimized. The research results show that the maximum equivalent stress of pump body structure is in the tongue, when the grid cell size is 6mm, the maximum equivalent stress is 36.843MPa; The maximum equivalent stress increases as the grid cell size decreases, and the unit number increases rapidly as the grid cell size decreases; When the wall thickness of pump is selected appropriately, the material can be saved about 6%, and the optimized structure of pump can be also meet the structural performance requirements.

Multi-Objective Optimization of a Bolt-Flange Structure

2011 ◽  
Vol 233-235 ◽  
pp. 2800-2804
Author(s):  
Yuan Dong Liu ◽  
Yi Hui Yin ◽  
Ying Chun Lu
Keyword(s):  
Response Surface ◽  
Design Method ◽  
Equivalent Stress ◽  
Optimization Method ◽  
Surface Model ◽  
Geometrical Parameters ◽  
Multi Objective Optimization ◽  
Surface Design ◽  
Multi Objective ◽  
Maximum Equivalent Stress

The bolt-flange structure is most one of joint mode, and stress and mass are its major performance parameters. The multi-object optimization of a bolt-flange structure can be performed by using Finite element method and optimization method unitedly. The response surface design method was employed to determine the combination of geometrical parameters to be designed of the bolt-flange structure. The stress of the bolt-flange structure which has the different geometrical parameters was numerically simulated and analyzed by using the software ANSYS. The response surface model is obtained. The optimized geometrical parameters of the bolt-flange structure were obtained by using MATLAB multi-objective optimization method. The results showed that the maximum equivalent stress in the optimized bolt-flange structure decreased 13.4% than that in the original one and the mass of the optimized bolt-flange structure was lower 14.3% than that of the original one.

scholarly journals Contact Model of Revolute Joint with Clearance Based on Fractal Theory

2018 ◽  
Vol 31 (1) ◽  
Author(s):  
Shi-Hua Li ◽  
Xue-Yan Han ◽  
Jun-Qi Wang ◽  
Jing Sun ◽  
Fu-Juan Li
Keyword(s):  
Fractal Theory ◽  
Contact Model ◽  
Revolute Joint

scholarly journals Surrogate-Based Optimization of Horizontal Axis Hydrokinetic Turbine Rotor Blades

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4045
Author(s):  
David Menéndez Arán ◽  
Ángel Menéndez
Keyword(s):  
Turbine Blade ◽  
Design Method ◽  
Optimization Method ◽  
Turbine Rotor ◽  
Computational Effort ◽  
Rotor Blades ◽  
Linear Functions ◽  
Cavitation Inception ◽  
Hydrokinetic Turbine ◽  
Blade Geometry

A design method was developed for automated, systematic design of hydrokinetic turbine rotor blades. The method coupled a Computational Fluid Dynamics (CFD) solver to estimate the power output of a given turbine with a surrogate-based constrained optimization method. This allowed the characterization of the design space while minimizing the number of analyzed blade geometries and the associated computational effort. An initial blade geometry developed using a lifting line optimization method was selected as the base geometry to generate a turbine blade family by multiplying a series of geometric parameters with corresponding linear functions. A performance database was constructed for the turbine blade family with the CFD solver and used to build the surrogate function. The linear functions were then incorporated into a constrained nonlinear optimization algorithm to solve for the blade geometry with the highest efficiency. A constraint on the minimum pressure on the blade could be set to prevent cavitation inception.

scholarly journals Finite Element Modeling of Residual Stress at Joint Interface of Titanium Alloy and 17-4PH Stainless Steel

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 629
Author(s):  
Nana Kwabena Adomako ◽  
Sung Hoon Kim ◽  
Ji Hong Yoon ◽  
Se-Hwan Lee ◽  
Jeoung Han Kim
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Modeling ◽  
Equivalent Stress ◽  
Stress Gradient ◽  
Joint Interface ◽  
Element Modeling ◽  
Actual Experiment ◽  
Maximum Equivalent Stress

Residual stress is a crucial element in determining the integrity of parts and lifetime of additively manufactured structures. In stainless steel and Ti-6Al-4V fabricated joints, residual stress causes cracking and delamination of the brittle intermetallic joint interface. Knowledge of the degree of residual stress at the joint interface is, therefore, important; however, the available information is limited owing to the joint’s brittle nature and its high failure susceptibility. In this study, the residual stress distribution during the deposition of 17-4PH stainless steel on Ti-6Al-4V alloy was predicted using Simufact additive software based on the finite element modeling technique. A sharp stress gradient was revealed at the joint interface, with compressive stress on the Ti-6Al-4V side and tensile stress on the 17-4PH side. This distribution is attributed to the large difference in the coefficients of thermal expansion of the two metals. The 17-4PH side exhibited maximum equivalent stress of 500 MPa, which was twice that of the Ti-6Al-4V side (240 MPa). This showed good correlation with the thermal residual stress calculations of the alloys. The thermal history predicted via simulation at the joint interface was within the temperature range of 368–477 °C and was highly congruent with that obtained in the actual experiment, approximately 300–450 °C. In the actual experiment, joint delamination occurred, ascribable to the residual stress accumulation and multiple additive manufacturing (AM) thermal cycles on the brittle FeTi and Fe2Ti intermetallic joint interface. The build deflected to the side at an angle of 0.708° after the simulation. This study could serve as a valid reference for engineers to understand the residual stress development in 17-4PH and Ti-6Al-4V joints fabricated with AM.

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