Deep learning-based surrogate model for fast multi-material topology optimization of IPM motor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hayaho Sato ◽  
Hajime Igarashi
Keyword(s):  
Finite Element ◽  
Deep Learning ◽  
Topology Optimization ◽  
Phase Angle ◽  
Surrogate Model ◽  
Fe Analysis ◽  
Current Phase ◽  
Cross Sectional ◽  
Content Type ◽  
Motor Image

Purpose This paper aims to present a deep learning–based surrogate model for fast multi-material topology optimization of an interior permanent magnet (IPM) motor. The multi-material topology optimization based on genetic algorithm needs large computational burden because of execution of finite element (FE) analysis for many times. To overcome this difficulty, a convolutional neural network (CNN) is adopted to predict the motor performance from the cross-sectional motor image and reduce the number of FE analysis. Design/methodology/approach To predict the average torque of an IPM motor, CNN is used as a surrogate model. From the input cross-sectional motor image, CNN infers dq-inductance and magnet flux to compute the average torque. It is shown that the average torque for any current phase angle can be predicted by this approach, which allows the maximization of the average torque by changing the current phase angle. The individuals in the multi-material topology optimization are evaluated by the trained CNN, and the limited individuals with higher potentials are evaluated by finite element method. Findings It is shown that the proposed method doubles the computing speed of the multi-material topology optimization without loss of search ability. In addition, the optimized motor obtained by the proposed method followed by simplification for manufacturing is shown to have higher average torque than a reference model. Originality/value This paper proposes a novel method based on deep learning for fast multi-material topology optimization considering the current phase angle.

Optimization design of titanium alloy connecting rod based on structural topology optimization

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bin Zheng ◽  
Yi Cai ◽  
Kelun Tang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Optimization Design ◽  
Equivalent Stress ◽  
Connecting Rod ◽  
Element Analysis ◽  
Content Type ◽  
The Finite Element Analysis ◽  
Maximum Equivalent Stress

Purpose The purpose of this paper is to realize the lightweight of connecting rod and meet the requirements of low energy consumption and vibration. Based on the structural design of the original connecting rod, the finite element analysis was conducted to reduce the weight and increase the natural frequencies, so as to reduce materials consumption and improve the energy efficiency of internal combustion engine. Design/methodology/approach The finite element analysis, structural optimization design and topology optimization of the connecting rod are applied. Efficient hybrid method is deployed: static and modal analysis; and structure re-design of the connecting rod based on topology optimization. Findings After the optimization of the connecting rod, the weight is reduced from 1.7907 to 1.4875 kg, with a reduction of 16.93%. The maximum equivalent stress of the optimized connecting rod is 183.97 MPa and that of the original structure is 217.18 MPa, with the reduction of 15.62%. The first, second and third natural frequencies of the optimized connecting rod are increased by 8.89%, 8.85% and 11.09%, respectively. Through the finite element analysis and based on the lightweight, the maximum equivalent stress is reduced and the low-order natural frequency is increased. Originality/value This paper presents an optimization method on the connecting rod structure. Based on the statics and modal analysis of the connecting rod and combined with the topology optimization, the size of the connecting rod is improved, and the static and dynamic characteristics of the optimized connecting rod are improved.

Finite element modeling and simulation of hip joints in elderly women: for development of protective clothing against fracture

2020 ◽  
Vol 32 (5) ◽  
pp. 661-675
Author(s):  
Jinhee Park ◽  
Yun Ja Nam
Keyword(s):  
Finite Element ◽  
Hip Joint ◽  
Human Body ◽  
Protective Clothing ◽  
Elderly Women ◽  
Hip Joints ◽  
Cross Sectional ◽  
Content Type ◽  
Protective Devices ◽  
Joint Fracture

PurposeFracture experiments on real human bodies to examine the protected positions and protective devices for the development of protective clothing to manage fractures is exceedingly difficult. Thus, the experimental design will have limitations, more of which are imposed if subjects are elderly people. To circumvent these limitations, this study proposes a finite element model of the hip joint in elderly women with virtual impact simulations that can replace actual fall and impact tests, and examine the positions and characteristics of fractures resulting from taking a fall.Design/methodology/approachThe hip joints were modeled after the average horizontal surface size and cross-sectional shapes of the lower extremities (waist to knee) in 439 elderly Korean women in that age group. The model was composed of bones, cartilages, and soft tissue.FindingsThe fracture was examined by comparing the maximum stress on the hip joint by applying a point force to its adjacent surface. The vulnerable part in the hip joint neck with a high risk of fracture risk on an impact could be determined and used to set the protective device attachment position.Originality/valueIt is significant that this study has developed a partial model of the human body that can be used for a relatively simple simulation by minimizing the highly complex human body as much as possible. Furthermore, the model is easily applicable to the designing of protected positions and protective devices for the development of special clothing, for hip joint fracture prevention.

scholarly journals Modeling the Bond Stress at Steel-Concrete Interface for Uncorroded and Corroded Reinforcing Steel

2021 ◽  
Author(s):  
Alaka Ghosh
Keyword(s):  
Finite Element ◽  
Bond Strength ◽  
Mass Loss ◽  
Fe Analysis ◽  
Nonlinear Finite Element ◽  
Reinforcing Steel ◽  
Sectional Area ◽  
Cross Sectional ◽  
Pullout Tests ◽  
Concrete Interface

Corrosion of reinforcing steel causes cracking and spalling of concrete structures, reduces the effective cross-sectional area of the reinforcing steel and the concrete simultaneously decreases the bond strength at the steel-concrete interface. The detrimental effect of corrosion on the service life of reinforced concrete structures highlights the need for modeling of bond strength between the corroded steel and the concrete. This research presents a nonlinear finite element model for the bond stress at the steel-concrete interface for both uncorroded and corroded reinforcing steel. The nonlinear finite element program ABAQUS is used for this purpose. The expanded volume of corroded product of reinforcing steel produces radial and hoop stresses which cause longitudinal cracks in the concrete. The increased longitudinal crack width, the loss of effective cross-sectional area of the steel and the concrete is also reduced due to the lubricating effect of flaky corroded layer. This research models the loss of contact pressure and the decrease of friction coefficient with the mass loss of the reinforcing steel. The model analyzes the pullout tests of Amleh (2002) and a good agreement is noted between the analytical and the experimental results. Both in FE analysis and experimental results, the loss of bond capacity is almost linear with mass loss of rebar. FE analysis and experiemental result show that, up to 5% mass loss, the bond capacity loss is moderate, at 10 to 15% mass loss, significant amount of bond capacity is lost and at about 20% mass almost all bond capacity is lost. The model is also validated by analyzing the pullout tests performed by Cabrera and Ghoddoussis (1992) and those by Al-Sulaimani et al.(1990).

scholarly journals Modeling the Bond Stress at Steel-Concrete Interface for Uncorroded and Corroded Reinforcing Steel

2021 ◽  
Author(s):  
Alaka Ghosh
Keyword(s):  
Finite Element ◽  
Bond Strength ◽  
Mass Loss ◽  
Fe Analysis ◽  
Nonlinear Finite Element ◽  
Reinforcing Steel ◽  
Sectional Area ◽  
Cross Sectional ◽  
Pullout Tests ◽  
Concrete Interface

Corrosion of reinforcing steel causes cracking and spalling of concrete structures, reduces the effective cross-sectional area of the reinforcing steel and the concrete simultaneously decreases the bond strength at the steel-concrete interface. The detrimental effect of corrosion on the service life of reinforced concrete structures highlights the need for modeling of bond strength between the corroded steel and the concrete. This research presents a nonlinear finite element model for the bond stress at the steel-concrete interface for both uncorroded and corroded reinforcing steel. The nonlinear finite element program ABAQUS is used for this purpose. The expanded volume of corroded product of reinforcing steel produces radial and hoop stresses which cause longitudinal cracks in the concrete. The increased longitudinal crack width, the loss of effective cross-sectional area of the steel and the concrete is also reduced due to the lubricating effect of flaky corroded layer. This research models the loss of contact pressure and the decrease of friction coefficient with the mass loss of the reinforcing steel. The model analyzes the pullout tests of Amleh (2002) and a good agreement is noted between the analytical and the experimental results. Both in FE analysis and experimental results, the loss of bond capacity is almost linear with mass loss of rebar. FE analysis and experiemental result show that, up to 5% mass loss, the bond capacity loss is moderate, at 10 to 15% mass loss, significant amount of bond capacity is lost and at about 20% mass almost all bond capacity is lost. The model is also validated by analyzing the pullout tests performed by Cabrera and Ghoddoussis (1992) and those by Al-Sulaimani et al.(1990).

Homogenization of multi-turn coil with elliptic cross-section using complex permeability

2019 ◽  
Vol 38 (3) ◽  
pp. 999-1008 ◽  
Author(s):  
Shogo Fujita ◽  
Hajime Igarashi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Elements ◽  
Cross Section ◽  
Fe Analysis ◽  
Complex Permeability ◽  
Elliptic Cross Section ◽  
Content Type ◽  
Elliptic Cross ◽  
Good Agreement

Purpose The tensor complex permeability of a multi-turn coil with elliptic cross-section is analytically expressed. In field analysis, a multi-turn coil can be modeled by the uniform material that has the present tensor complex permeability. It is shown that the frequency characteristic of the present tensor complex permeability is in good agreement with that evaluated by finite element method applied to a unit cell of the multi-turn coil region. Design/methodology/approach The authors introduce a new method to evaluate the complex permeability of a multi-turn rectangular coil. To obtain the complex permeability of a rectangular coil in a closed form, it is approximated as an elliptic coil. Because the rectangular coil has different complex permeabilities in the vertical and horizontal directions, the complex permeability have to be defined in a tensor form. It suffices to discretize the coil region into rather coarse finite elements without considering the skin depth in contrast to the conventional finite element method. Findings The proposed method is shown to give the impedance of multi-turn coils which is in good agreement with results obtained by the conventional finite element (FE) analysis. By extending the proposed approach, the authors can easily perform 3D FE analysis without difficulty in discretization of the coil region with fairly fine finite elements. Moreover, they found that the approximation of rectangular coils as the elliptic coils is valid for analysis of quasi-static fields using this homogenization method. Originality/value The novelty of this study is in the approximation of the rectangular coils with elliptic coils, and the complex permeability for them is formulated here in a closed form. The proposed formula includes that for the round coils. Using the present method, the authors analyze the rectangular coils without fine discretization.

An adaptive nonlinear finite element analysis of minimal surface problem based on element energy projection technique

2020 ◽  
Vol 37 (8) ◽  
pp. 2847-2869
Author(s):  
Kaifeng Jiang ◽  
Si Yuan ◽  
Qinyan Xing
Keyword(s):  
Finite Element ◽  
Minimal Surface ◽  
Error Control ◽  
Nonlinear Problems ◽  
Fe Analysis ◽  
Nonlinear Finite Element ◽  
Maximum Norm ◽  
Element Analysis ◽  
Content Type ◽  
Element Energy Projection

Purpose This paper aims to propose a new adaptive strategy for two-dimensional (2D) nonlinear finite element (FE) analysis of the minimal surface problem (MSP) based on the element energy projection (EEP) technique. Design/methodology/approach By linearizing nonlinear problems into a series of linear problems via the Newton method, the EEP technique, which is an effective and reliable point-wise super-convergent displacement recovery strategy for linear FE analysis, can be directly incorporated into the solution procedure. Accordingly, a posteriori error estimate in maximum norm was established and an adaptive 2D nonlinear FE strategy of h-version mesh refinement was developed. Findings Three classical known surfaces, including a singularity problem, were analysed. Moreover, an example whose analytic solution is unavailable was considered and a comparison was made between present results and those computed by the MATLAB PDE toolbox. The results show that the adaptively-generated meshes reflect the difficulties inherent in the problems and the proposed adaptive analysis can produce FE solutions satisfying the user-preset error tolerance in maximum norm with a fair adaptive convergence rate. Originality/value The EEP technique for linear FE analysis was extended to the nonlinear procedure of MSP and can be expected to apply to other 2D nonlinear problems. The employment of the maximum norm makes point-wisely error control on the sought surfaces possible and makes the proposed method distinguished from other adaptive FE analyses.

Multistage topology optimization of induction heating apparatus in time domain electromagnetic field with magnetic nonlinearity

2019 ◽  
Vol 38 (3) ◽  
pp. 1009-1022
Author(s):  
Hiroshi Masuda ◽  
Yoshifumi Okamoto ◽  
Shinji Wakao
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Induction Heating ◽  
Time Domain ◽  
Computation Time ◽  
Design Domain ◽  
Element Mesh ◽  
Content Type ◽  
Actual Application ◽  
Application Model

Purpose The purpose of this paper is to solve efficiently the topology optimization (TO) in time domain problem with magnetic nonlinearity requiring a large-scale finite element mesh. As an actual application model, the proposed method is applied to induction heating apparatus. Design/methodology/approach To achieve TO with efficient computation time, a multistage topology is proposed. This method can derive the optimum structure by repeatedly reducing the design domain and regenerating the finite element mesh. Findings It was clarified that the structure derived from proposed method can be similar to the structure derived from the conventional method, and that the computation time can be made more efficient by parameter tuning of the frequency and volume constraint value. In addition, as a time domain induction heating apparatus problem of an actual application model, an optimum topology considering magnetic nonlinearity was derived from the proposed method. Originality/value Whereas the entire design domain must be filled with small triangles in the conventional TO method, the proposed method requires finer mesh division of only the stepwise-reduced design domain. Therefore, the mesh scale is reduced, and there is a possibility that the computation time for TO can be shortened.

A comprehensive nonlinear finite element modelling and parametric analysis of reinforced concrete beams

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pandimani Pandimani ◽  
Markandeya Raju Ponnada ◽  
Yesuratnam Geddada
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Ultimate Load ◽  
Fe Analysis ◽  
Fe Model ◽  
Rc Beams ◽  
Content Type ◽  
Bond Slip ◽  
Slip Mechanism

Purpose This study aims to present comprehensive nonlinear material modelling techniques and simulations of reinforced concrete (RC) beams subjected to short-term monotonic static load using the robust and reliable general-purpose finite element (FE) software ANSYS. A parametric study is carried out to analyse the flexural and ductility behaviour of RC beams under various influencing parameters. Design/methodology/approach To develop and validate the numerical FE models, a total of four experimentally tested simply supported RC beams are taken from the available literature and two beams are selected from each author. The concrete, steel reinforcements, bond-slip mechanism, loading and supporting plates are modelled using SOLID65, LINK180, COMBIN39 and SOLID185 elements, respectively. The validated models are then used to conduct parametric FE analysis to investigate the effect of concrete compressive strength, percentage of tensile reinforcement, compression reinforcement ratio, transverse shear reinforcement, bond-slip mechanism, concrete compressive stress-strain constitutive models, beam symmetry and varying overall depth of beam on the ultimate load-carrying capacity and ductility behaviour of RC beams. Findings The developed three-dimensional FE models can able to capture the load and midspan deflections at critical points, the accurate yield point of steel reinforcements, the formation of initial and progressive concrete crack patterns and the complete load-deflection curves of RC beams up to ultimate failure. From the numerical results, it can be concluded that the FE model considering the bond-slip effect with Thorenfeldt’s concrete compressive stress-strain model exhibits a better correlation with the experimental data. Originality/value The ultimate load and deflection results of validated FE models show a maximum deviation of less than 10% and 15%, respectively, as compared to the experimental results. The developed model is also capable of capturing concrete failure modes accurately. Overall, the FE analysis results were found quite acceptable and compared well with the experimental data at all loading stages. It is suggested that the proposed FE model is a practical and reliable tool for analyzing the flexural behaviour of RC members and can be used for performing parametric studies.

Finite-element modeling of partially prestressed concrete beams with unbonded tendon under monotonic loadings

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pandimani ◽  
Markandeya Raju Ponnada ◽  
Yesuratnam Geddada
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Nonlinear Response ◽  
Concrete Beams ◽  
Fe Analysis ◽  
Material Behavior ◽  
Fe Model ◽  
Ansys Software ◽  
Content Type ◽  
Prestressing Tendon

Purpose The partially prestressed concrete beam with unbonded tendon is still an active field of research because of the difficulty in analyzing and understanding its behavior. The finite-element (FE) simulation of such beams using numerical software is very scarce in the literature and therefore this study is taken to demonstrate the modeling aspects of unbonded partially prestressed concrete (UPPSC) beams. This study aims to present the three-dimensional (3-D) nonlinear FE simulations of UPPSC beams subjected to monotonic static loadings using the numerical analysis package ANSYS. Design/methodology/approach The sensitivity study is carried out with three different mesh densities to obtain the optimum elements that reflect on the load–deflection behavior of numerical models, and the model with optimum element density is used further to model all the UPPSC beams in this study. Three half-symmetry FE model is constructed in ANSYS parametric design language domain with proper boundary conditions at the symmetry plane and support to achieve the same response as that of the full-scale experimental beam available in the literature. The linear and nonlinear material behavior of prestressing tendon and conventional steel reinforcements, concrete and anchorage and loading plates are modeled using link180, solid65 and solid185 elements, respectively. The Newton–Raphson iteration method is used to solve the nonlinear solution of the FE models. Findings The evolution of concrete cracking at critical loadings, yielding of nonprestressed steel reinforcements, stress increment in the prestressing tendon, stresses in concrete elements and the complete load–deflection behavior of the UPPSC beams are well predicted by the proposed FE model. The maximum discrepancy of ultimate moments and deflections of the validated FE models exhibit 13% and −5%, respectively, in comparison with the experimental results. Practical implications The FE analysis of UPPSC beams is done using ANSYS software, which is a versatile tool in contrast to the experimental testing to study the stress increments in the unbonded tendons and assess the complete nonlinear response of partially prestressed concrete beams. The validated numerical model and the techniques presented in this study can be readily used to explore the parametric analysis of UPPSC beams. Originality/value The developed model is capable of predicting the strength and nonlinear behavior of UPPSC beams with reasonable accuracy. The load–deflection plot captured by the FE model is corroborated with the experimental data existing in the literature and the FE results exhibit good agreement against the experimentally tested beams, which expresses the practicability of using FE analysis for the nonlinear response of UPPSC beams using ANSYS software.

Sign in / Sign up

Export Citation Format

Share Document