Complex-valued Modal Loss Factor Maximization for an Unconstrained Damping Layout with Topology Optimization

2017 ◽  
Vol 27 (7) ◽  
pp. 900-907
Author(s):  
Sun-Yong Kim
Keyword(s):  
Topology Optimization ◽  
Loss Factor ◽  
Complex Valued

scholarly journals Microstructural Topology Optimization of Constrained Layer Damping on Plates for Maximum Modal Loss Factor of Macrostructures

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhanpeng Fang ◽  
Lei Yao ◽  
Shuxia Tian ◽  
Junjian Hou
Keyword(s):  
Topology Optimization ◽  
Loss Factor ◽  
Strain Energy ◽  
Design Method ◽  
Optimization Method ◽  
Constrained Layer Damping ◽  
Viscoelastic Materials ◽  
Modal Strain Energy ◽  
Design Variables ◽  
Microstructural Topology Optimization

This paper presents microstructural topology optimization of viscoelastic materials for the plates with constrained layer damping (CLD) treatments. The design objective is to maximize modal loss factor of macrostructures, which is obtained by using the Modal Strain Energy (MSE) method. The microstructure of the viscoelastic damping layer is composed of 3D periodic unit cells. The effective elastic properties of the unit cell are obtained through the strain energy-based method. The density-based topology optimization is adopted to find optimal microstructures of viscoelastic materials. The design sensitivities of modal loss factor with respect to the design variables are analyzed and the design variables are updated by Method of Moving Asymptotes (MMA). Numerical examples are given to demonstrate the validity of the proposed optimization method. The effectiveness of the optimal design method is illustrated by comparing a solid and an optimized cellular viscoelastic material as applied to the plates with CLD treatments.

Topology Optimization for Constrained Layer Damping Plates Using Evolutionary Structural Optimization Method

2014 ◽  
Vol 894 ◽  
pp. 158-162 ◽  
Author(s):  
Bing Qin Wang ◽  
Bing Li Wang ◽  
Zhi Yuan Huang
Keyword(s):  
Topology Optimization ◽  
Energy Dissipation ◽  
Structural Optimization ◽  
Design Variable ◽  
Loss Factor ◽  
Optimization Approach ◽  
Constrained Layer Damping ◽  
Modal Strain Energy ◽  
Evolutionary Structural Optimization ◽  
Constrained Damping

The evolutionary structural optimization (ESO) is used to optimize constrained damping layer structure. Considering the vibration and energy dissipation mode of the plate with constrained layer damping treatment, the elements of constrained damping layers and modal loss factor are considered as design variable and objective function, while damping material consumption is considered as a constraint. The sensitivity of modal loss factor to design variable is further derived using modal strain energy analysis method. Numerical example is used to demonstrate the effectiveness of the proposed topology optimization approach. The results show that vibration energy dissipation of the plates can be enhanced by the optimal constrained layer damping layout.

Topology Optimization of Constrained Damping Layer Treatments

2002 ◽  
Author(s):  
Arnold Lumsdaine
Keyword(s):  
Topology Optimization ◽  
Loss Factor ◽  
Elastic Beam ◽  
Forced Response ◽  
Optimization Process ◽  
Programming Algorithm ◽  
Optimal Topology ◽  
Modal Strain Energy ◽  
Constrained Damping ◽  
Half Power

The aim of this research is to determine the optimal shape of a constrained viscoelastic damping layer on an elastic beam by means of topology optimization. The optimization objective is to maximize the system loss factor for the first resonance frequency of the base beam. All previous optimal design studies on viscoelastic lamina have been size or shape optimization studies, assuming a certain topology for the damping treatment. In this study, this assumption is relaxed, allowing an optimal topology to emerge. The loss factor is computed using the Modal Strain Energy method in the optimization process. Loss factor results are validated by using the half-power bandwidth method, which requires obtaining the forced response of the structure. The ABAQUS finite element code is used to model the structure with two-dimensional continuum elements. The optimization code uses a Sequential Quadratic Programming algorithm. Results show that significant improvements in damping performance, on the order of 100% to 300%, are obtained by optimizing the constrained damping layer topology. A novel topology for the constraining layer emerges through the optimization process.

Topology Optimization of Viscoelastic Materials Distribution of Damped Sandwich Plate Composite

2013 ◽  
Vol 347-350 ◽  
pp. 1182-1186 ◽  
Author(s):  
Zhan Xin Liu ◽  
Hong Guan ◽  
Wei Guang Zhen
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Objective Function ◽  
Loss Factor ◽  
Isotropic Material ◽  
Sandwich Plate ◽  
Viscoelastic Layer ◽  
Plate Vibration ◽  
Viscoelastic Materials ◽  
Optimum Distribution

Optimum distribution of viscoelastic materials of damped sandwich plate composite for suppressing plate vibration is investigated. A solid isotropic material with penalization model is described based on the proposed interface finite element of viscoelastic layer. The objective function is chosen as maximization of the modal loss factor. Numerical results show that the optimum distributions of viscoelastic materials are mainly at the place where large shear displacements would be happened.

scholarly journals Modifications to the Method of Modal Strain Energy for Improved Estimates of Loss Factors for Damped Structures

2007 ◽  
Vol 14 (5) ◽  
pp. 339-353 ◽  
Author(s):  
Peter J. Torvik ◽  
Brian Runyon
Keyword(s):  
Loss Factor ◽  
Strain Energy ◽  
Prototype System ◽  
Constrained Layer Damping ◽  
Modal Strain Energy ◽  
High Loss ◽  
Analysis And Design ◽  
Dissipative Material ◽  
Complex Valued ◽  
Loss Factors

The method of Modal Strain Energy (MSE) enables predictions of modal loss factors for vibrating systems from finite element analyses without evaluation of a complex-valued frequency response or a complex-valued frequency. While the method is simple, some error results; especially if the dissipative material has the high loss factor characteristic of materials added to increase system damping. Several methods for reducing this error through modifications to MSE have been suggested. In this work, the exact loss factor for a simple mechanical system is found. The method of Modal Strain Energy (MSE) is then used to find the loss factor for that prototype system and errors are evaluated in terms of system parameters. Comparisons are also made to predictions with several modifications to MSE. A modification due to Rongong is found to provide significant improvement. The use of this modification together with MSE is shown to lead to lower and upper bounds for the system loss factor. As the prototype system is shown to be mechanically equivalent to constrained layer damping configurations, the findings are applicable to the analysis and design of optimized sandwich beams, plates, and damping tapes. Results are given for beams and plates with constrained layer treatments.

Multi-material topology optimization of viscoelastically damped structures using a parametric level set method

2015 ◽  
Vol 23 (15) ◽  
pp. 2430-2443 ◽  
Author(s):  
Max van der Kolk ◽  
Gijs J van der Veen ◽  
Jan de Vreugd ◽  
Matthijs Langelaar
Keyword(s):  
Topology Optimization ◽  
Level Set ◽  
Viscoelastic Material ◽  
High Performance ◽  
Dynamic Performance ◽  
Viscoelastic Behavior ◽  
Optimization Approach ◽  
Adjoint Sensitivity ◽  
Damping Characteristics ◽  
Complex Valued

The design of high performance instruments often involves the attenuation of poorly damped resonant modes. Current design practices typically rely on informed trial and error based modifications to improve dynamic performance. In this article, a multi-material topology optimization approach is presented as a systematic methodology to develop structures with optimal damping characteristics. The proposed method applies a multi-material, parametric, level set-based topology optimization to simultaneously distribute structural and viscoelastic material to optimize damping characteristics. The viscoelastic behavior is represented by a complex-valued material modulus resulting in a complex-valued eigenvalue problem. The structural loss factor is used as objective function during the optimization and is calculated using the complex-valued eigenmodes. An adjoint sensitivity analysis is presented that provides an analytical expression for the corresponding sensitivities. Multiple numerical examples are treated to illustrate the effectiveness of the approach and the influence of different viscoelastic material models on the optimized designs is studied. The optimization routine is able to generate designs for a number of eigenmodes and to attenuate a resonant mode of an existing structure.

Complex-valued Neural Networks

2011 ◽  
Vol 131 (1) ◽  
pp. 2-8
Author(s):  
Akira Hirose
Keyword(s):  
Neural Networks ◽  
Complex Valued
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