Coupling Moving Morphable Voids and Components Based Topology Optimization of Hydrogel Structures Involving Large Deformation

2021 ◽  
Vol 89 (1) ◽  
Author(s):  
Yisong Qiu ◽  
Shuaiqi Zhang ◽  
Weisheng Zhang ◽  
Hongfei Ye ◽  
Hongwu Zhang ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Large Deformation ◽  
Optimization Design ◽  
Density Field ◽  
Adjoint Sensitivity ◽  
Topology Optimization Problem ◽  
Strain Energy Density Function ◽  
Design Variables ◽  
Component Approach ◽  
Gradient Based

Abstract A coupling of moving morphable void and component approach for the topology optimization of hydrogel structures involving recoverable large deformation is proposed in this paper. In this approach, the geometric parameters of moving morphable voids and components are set as design variables to respectively describe the outline and material distribution of hydrogel structures for the first time. To facilitate the numerical simulation of large deformation behavior of hydrogel structures during the optimization process, the design variables are mapped to the density field of the design domain and the density field is then used to interpolate the strain energy density function of the element. Furthermore, the adjoint sensitivity of the optimization formulation is derived and combined with the gradient-based algorithm to solve the topology optimization problem effectively. Finally, two representative numerical examples of the optimization of isotropic hydrogel structures are used to prove the effectiveness of the proposed method, and the optimization design of an anisotropic bionic hydrogel structure is presented to illustrate the applicability of the method. Experimental results are also presented to demonstrate that the explicit topologies obtained from the method can be directly used in the manufacture of hydrogel-based soft devices.

Topology Optimization Using Node-Based Smoothed Finite Element Method

2015 ◽  
Vol 07 (06) ◽  
pp. 1550085 ◽  
Author(s):  
Z. C. He ◽  
G. Y. Zhang ◽  
L. Deng ◽  
Eric Li ◽  
G. R. Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Topology Optimization ◽  
Optimization Design ◽  
Solid Mechanics ◽  
Optimality Criteria ◽  
Topology Optimization Problem ◽  
Design Variables ◽  
Smoothed Finite Element Method ◽  
Element Method

The node-based smoothed finite element method (NS-FEM) proposed recently has shown very good properties in solid mechanics, such as providing much better gradient solutions. In this paper, the topology optimization design of the continuum structures under static load is formulated on the basis of NS-FEM. As the node-based smoothing domain is the sub-unit of assembling stiffness matrix in the NS-FEM, the relative density of node-based smoothing domains serves as design variables. In this formulation, the compliance minimization is considered as an objective function, and the topology optimization model is developed using the solid isotropic material with penalization (SIMP) interpolation scheme. The topology optimization problem is then solved by the optimality criteria (OC) method. Finally, the feasibility and efficiency of the proposed method are illustrated with both 2D and 3D examples that are widely used in the topology optimization design.

On the Topology Optimization Design for the Stereolithography Based Investment Casting Model

2010 ◽  
Vol 139-141 ◽  
pp. 1464-1467 ◽  
Author(s):  
Ji Hong Zhu ◽  
Wei Hong Zhang ◽  
Xiao Jun Gu
Keyword(s):  
Topology Optimization ◽  
Investment Casting ◽  
Optimization Design ◽  
Coefficient Of Thermal Expansion ◽  
Crack Problem ◽  
Optimization Method ◽  
Ceramic Shell ◽  
Topology Optimization Problem ◽  
Design Variables ◽  
Material Layout

The purpose of this paper is to avoid the crack problem of the ceramic shell during the burnout procedure of the rapid investment casting using stereolithograghy (SLA) model. Since the coefficient of thermal expansion of the SLA model is much higher than the coefficient of the ceramic shell, the internal structural patterns have to be properly designed to reduce the stress level in the ceramic shell. A topology optimization method is proposed here to find better microstructure designs to satisfy both the strength of the ceramic shell and the stiffness of the SLA model itself. Taking the arrayed microstructure into account, the pseudo-densities of the SLA model elements to describe the material layout are defined and assumed as the design variables. By deriving the design sensitivities, the topology optimization problem is solved with reasonable numerical results generated.

scholarly journals An explicit topology optimization method using moving polygonal morphable voids (MPMVs)

2020 ◽  
Vol 23 (2) ◽  
pp. 536-540 ◽  
Author(s):  
Hoang Van-Nam
Keyword(s):  
Topology Optimization ◽  
Design Space ◽  
Optimization Method ◽  
Density Field ◽  
Optimization Approach ◽  
Design Variables ◽  
Mesh Independence ◽  
Gradient Based ◽  
Element Density ◽  
Optimization Solvers

Introduction: Conventional topology optimization approaches are implemented in an implicit manner with a very large number of design variables, requiring large storage and computation costs. In this study, an explicit topology optimization approach is proposed by movonal morphable voids whose geometry parameters are considered as design variables. Methods: Each polygonal void plays as an empty-material zone that can move, change its shapes, and overlap with its neighbors in a design space. The geometry eters of MPMVs consisting of the coordinates of polygonal vertices are utilized to render the structure in the design domain in an element density field. The density function of the elements located inside polygonal voids is described by a smooth exponential function that allows utilizing gradient-based optimization solvers. Results & Conclusion: Compared with conventional topology optimization approaches, the MPMV approach uses fewer design variables, ensure mesh-independence solution without filtering techniques or perimeter constraints. Several numerical examples are solved to validate the efficiency of the MPMV approach.

Efficient Sensitivity Analysis for Multibody Dynamics Systems Using an Iterative Steps Method With Application in Topology Optimization

2011 ◽  
Author(s):  
Guang Dong ◽  
Zheng-Dong Ma ◽  
Gregory Hulbert ◽  
Noboru Kikuchi ◽  
Sudhakar Arepally ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Topology Optimization ◽  
Multibody Dynamics ◽  
Optimization Problem ◽  
Finite Difference Methods ◽  
Analysis Method ◽  
Topology Optimization Problem ◽  
Design Variables ◽  
Sensitivity Analysis Method ◽  
Rotational Motions

Efficient and reliable sensitivity analyses are critical for topology optimization, especially for multibody dynamics systems, because of the large number of design variables and the complexities and expense in solving the state equations. This research addresses a general and efficient sensitivity analysis method for topology optimization with design objectives associated with time dependent dynamics responses of multibody dynamics systems that include nonlinear geometric effects associated with large translational and rotational motions. An iterative sensitivity analysis relation is proposed, based on typical finite difference methods for the differential algebraic equations (DAEs). These iterative equations can be simplified for specific cases to obtain more efficient sensitivity analysis methods. Since finite difference methods are general and widely used, the iterative sensitivity analysis is also applicable to various numerical solution approaches. The proposed sensitivity analysis method is demonstrated using a truss structure topology optimization problem with consideration of the dynamic response including large translational and rotational motions. The topology optimization problem of the general truss structure is formulated using the SIMP (Simply Isotropic Material with Penalization) assumption for the design variables associated with each truss member. It is shown that the proposed iterative steps sensitivity analysis method is both reliable and efficient.

Topology Optimization Design of High Pressure Storage Tank Structure

2012 ◽  
Vol 430-432 ◽  
pp. 828-833
Author(s):  
Qiu Sheng Ma ◽  
Yi Cai ◽  
Dong Xing Tian
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Topology Optimization ◽  
Storage Tank ◽  
Optimization Design ◽  
Influence Factors ◽  
Element Model ◽  
Design Variables ◽  
Calculation Results ◽  
Pressure Storage

In this paper, based on ANSYS the topology optimization design for high pressure storage tank was studied by the means of the finite element structural analysis and optimization. the finite element model for optimization design was established. The design variables influence factors and rules on the optimization results are summarized. according to the calculation results the optimal design result for tank is determined considering the manufacturing and processing. The calculation results show that the method is effective in optimization design and provide the basis to further design high pressure tank.

Optimal shape design of a brake calliper for squeal noise reduction considering system instability

2010 ◽  
Vol 224 (7) ◽  
pp. 909-925 ◽  
Author(s):  
H J Soh ◽  
J-H Yoo
Keyword(s):  
Topology Optimization ◽  
Design Process ◽  
Optimization Design ◽  
Parametric Design ◽  
Unstable Mode ◽  
Complex Eigenvalue ◽  
Noise Generation ◽  
Design Variables ◽  
Asymmetric Shape ◽  
Squeal Noise

Squeal is a noise phenomenon occurring in the last stage of automobile braking with a high-frequency sound. It is very difficult to express the phenomenon using a mathematical model, since the origin of squeal noise is physically complex. However, the possibility of squeal generation can be predicted by solving the vibration equation of the self-excited system using the complex eigenvalue analysis method. The results of the method are expressed as the magnitude of the unstable mode, and the generation of squeal noise can be prevented by reducing the magnitude of the unstable mode of the brake system. The objective of this research is to determine the optimal design process focused on the calliper housing shape to suppress squeal noise generation by reducing the system instability. The objective function is set to minimize the real part of the complex eigenvalue, i.e. the instability index. In the optimization design process, the design variable for topology optimization is established by focusing on the finger part of the calliper housing, which transmits the braking pressure to the pad lining. To supplement the complex shape generated by the topology optimization process, parametric design variables are selected for the subsequent process. Parameters are set to adjust the housing finger stiffness and are defined by considering the topology optimization result. Finally, the asymmetric shape of the calliper housing is obtained to reduce squeal noise generation.

scholarly journals Gradient-based topology optimization of soft dielectrics as tunable phononic crystals

2021 ◽  
Author(s):  
Atul Kumar Sharma ◽  
Gal Shmuel ◽  
Oded Amir
Keyword(s):  
Topology Optimization ◽  
Electric Fields ◽  
Computational Cost ◽  
Optimization Method ◽  
Phononic Crystals ◽  
Frequency Bands ◽  
Design Variables ◽  
Gradient Based ◽  
Soft Dielectrics ◽  
Design Freedom

Dielectric elastomers are active materials that undergo large deformations and change their instantaneous moduli when they are actuated by electric fields. By virtue of these features, composites made of soft dielectrics can filter waves across frequency bands that are electrostatically tunable. To date, to improve the performance of these adaptive phononic crystals, such as the width of these bands at the actuated state, metaheuristics-based topology optimization was used. However, the design freedom offered by this approach is limited because the number of function evaluations increases exponentially with the number of design variables. Here, we go beyond the limitations of this approach, by developing an efficient gradient-based topology optimization method. The numerical results of the method developed here demonstrate prohibited frequency bands that are indeed wider than those obtained from the previous metaheuristics-based method, while the computational cost to identify them is reduced by orders of magnitude.

Topology Optimization Design of Pre-Stressed Plane Entity Steel Structure with the Constrains of Stress and Displacement

2014 ◽  
Vol 945-949 ◽  
pp. 1216-1222 ◽  
Author(s):  
Li Yao ◽  
Yun Xia Gao ◽  
Hai Jun Yang
Keyword(s):  
Topology Optimization ◽  
Optimization Design ◽  
Mechanical Performance ◽  
Steel Structure ◽  
Structural Topology ◽  
Unit Size ◽  
Structure Topology ◽  
Design Variables ◽  
Displacement Sensitivity ◽  
Low Sensitivity

For the prestressed plane entitiy steel structure topology optimization design which design variables include the cable pretension value, unit size and the structural topology, the optimized mathematical model which objective function is the minimum structural weight is established with consideration of the constrains of stress and displacement. As for the solving method, firstly we need to determine the pretension applying to the cable according to full stress design and choose the unit size; then we need to conduct displacement sensitivity analysis to delete the low sensitivity unit to realize the structural topology optimization design. The example result is in conformity with the corresponding system of mechanical performance, and it indicates that the method proposed in this paper is effective.

Research on Three-Dimensional Topology Optimization for the Bed of NC Gear Shaper

2013 ◽  
Vol 690-693 ◽  
pp. 2821-2825
Author(s):  
Qi Hua Tian ◽  
Ran Tao ◽  
Yi Xian Du
Keyword(s):  
Topology Optimization ◽  
Optimization Design ◽  
Interpolation Method ◽  
Geometric Model ◽  
Three Dimensional ◽  
Optimality Criteria ◽  
Material Distribution ◽  
Design Variables ◽  
Three Dimensional Finite Element ◽  
Bed Material

Taking minimum compliance of the bed of YKS5120B-3 NC gear shaper as the optimization objective, and the three-dimensional finite element relative density as design variables, the three-dimensional topology optimization mathematical model is established based on the interpolation method of solid isotropic material. The optimality criteria algorithm is used to update design variables. Topology optimization design of loaded bed is conducted and the optimal bed material distribution in the design domain is obtained. The new geometric model of the bed is reconstructed according to the optimal bed material distribution. Comparing the static analyses results of original model of the bed with reconstructed model of the bed, the correctness and the validity of the proposed method is verified.

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