scholarly journals Some Progress on Parallel Modal and Vibration Analysis Using the JAUMIN Framework

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xuanhua Fan ◽  
Keying Wang ◽  
Shifu Xiao ◽  
Qingkai Liu ◽  
Zeyao Mo
Keyword(s):  
Vibration Analysis ◽  
Numerical Experiments ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
High Efficiency ◽  
Parallel Implementation ◽  
Solution System ◽  
Element Analysis ◽  
Parallel Solution ◽  
Complex Equipment

In the development of large and complex equipment, a large-scale finite element analysis (FEA) with high efficiency is often strongly required. This paper provides some progress on parallel solution of large-scale modal and vibration FE problems. Some predominant algorithms for modal and vibration analysis are firstly reviewed and studied. Based on the newly developed JAUMIN framework, the corresponding procedures are developed and integrated to form a parallel modal and vibration solution system; the details of parallel implementation are given. Numerical experiments are carried out to evaluate the parallel scalability of our procedures, and the results show that the maximum solution scale attains ninety million degrees of freedom (DOFs) and the maximum parallel CPU processors attain 8192 with favorable computing efficiency.

scholarly journals Massively Parallel CFD Simulation Software: CCFD Development and Optimization Based on Sunway TaihuLight

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Xiazhen Liu ◽  
Zhonghua Lu ◽  
Wu Yuan ◽  
Wenpeng Ma ◽  
Jian Zhang
Keyword(s):  
Large Scale ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Domain Decomposition Method ◽  
Weighted Graph ◽  
Simulation Software ◽  
Parallel Solution ◽  
Software Structure ◽  
Sunway Taihulight ◽  
Limiting Condition

A parallel framework software, CCFD, based on the structure grid, and suitable for parallel computing of super-large-scale structure blocks, is designed and implemented. An overdecomposition method, in which the load balancing strategy is based on the domain decomposition method, is designed for the graph subdivision algorithm. This method takes computation and communication as the limiting condition and realizes the load balance between blocks by dividing the weighted graph. The fast convergence technique of a high-efficiency parallel geometric multigrid greatly improves the parallel efficiency and convergence speed of CCFD software. This paper introduces the software structure, process invocations, and calculation method of CCFD and introduces a hybrid parallel acceleration technology based on the Sunway TaihuLight heterogeneous architecture. The results calculated by Onera-M6 and DLR-F6 standard model show that the software structure and method in this paper are feasible and can meet the requirements of a large-scale parallel solution.

Large Scale Finite Element Analysis Via Assembly-Free Deflated Conjugate Gradient

2014 ◽  
Vol 14 (4) ◽  
Author(s):  
Praveen Yadav ◽  
Krishnan Suresh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Conjugate Gradient ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Solid Mechanics ◽  
Processing Unit ◽  
Element Analysis ◽  
Central Processing ◽  
Computational Bottleneck

Large-scale finite element analysis (FEA) with millions of degrees of freedom (DOF) is becoming commonplace in solid mechanics. The primary computational bottleneck in such problems is the solution of large linear systems of equations. In this paper, we propose an assembly-free version of the deflated conjugate gradient (DCG) for solving such equations, where neither the stiffness matrix nor the deflation matrix is assembled. While assembly-free FEA is a well-known concept, the novelty pursued in this paper is the use of assembly-free deflation. The resulting implementation is particularly well suited for large-scale problems and can be easily ported to multicore central processing unit (CPU) and graphics-programmable unit (GPU) architectures. For demonstration, we show that one can solve a 50 × 106 degree of freedom system on a single GPU card, equipped with 3 GB of memory. The second contribution is an extension of the “rigid-body agglomeration” concept used in DCG to a “curvature-sensitive agglomeration.” The latter exploits classic plate and beam theories for efficient deflation of highly ill-conditioned problems arising from thin structures.

Vibration Analysis of Wind Turbine via a Multibody Dynamics Approach

2009 ◽  
Author(s):  
Shanzhong Shawn Duan
Keyword(s):  
Potential Energy ◽  
Data Storage ◽  
Wind Turbines ◽  
Vibration Analysis ◽  
Degrees Of Freedom ◽  
Rigid Bodies ◽  
Beam Model ◽  
Element Analysis ◽  
Plastic Properties ◽  
Lumped Model

In this paper, a lumped model of horizontal axis wind turbines (HAWT) is presented for modal and vibration analysis. Motion modes such as tower fore and aft, tower side to side, blade flap, blade edge, and tower axial torsion are considered. A multibody modeling approach is used to represent the structure and components of a HAWT. A continuous component in wind turbines may be divided as discrete rigid bodies linked by proper types of joints with springs and dampers for couplings. Joints are used to describe the degrees of freedom of the component’s deformation. Springs and dampers are added to accommodate the component’s elastic and plastic properties. For example the tower is modeled as discrete rigid bodies linked by universal joints, which allow three degrees of freedom (DOF) from one torsional and two bending motions of the tower, and torsional springs are added between bodies to accommodate elastic property of the tower. The potential energy of the springs equals to the potential energy of the continuous tower, which may be represented by Timoshenko-beam model. Thus the spring stiffness is calculated based on the potential energy equivalence. Equations of motion of wind turbines are derived via Kane’s dynamical method. Modal and vibration analysis are further carried out based on this lumped multibody model. As a comparison with other approaches such as finite element analysis (FEA) that requires high data storage and long simulation time, this approach may provide a low fidelity simulation model and tool, which is suitable for analysis of dynamic loads, modal, and vibration of wind turbines with respect to fixed and moving references at high computational efficiency and low simulation costs. The approach is also a good candidate for simulating dynamical behaviors of wind turbines and preventing their fatigue failures in time domain.

scholarly journals Finite elements with continuous stress fields in calculation of folded prismatic thin-walled rods and shells

2018 ◽  
Vol 196 ◽  
pp. 01018
Author(s):  
Sergey Nazarenko ◽  
Nina Blokhina
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Stress Fields ◽  
Displacement Fields ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Shell Finite Element ◽  
Rectangular Shell

The article deals with methods of creating a rectangular wall-beam finite element with eight degrees of freedom per node and continuous stress fields along the boundaries. This effect is achieved by specifying displacement fields in the plane of the element in forms similar to those in finite elements of Bogner, Fox, and Schmitt plate. The article provides algebraic expressions for displacement forms; methods of forming reaction and stress matrices are also considered. Test calculations carried out with the help of “Computational mechanics” FEM complex have proved high efficiency of the finite element analysis performed. A rectangular shell finite element with twelve degrees of freedom per node was developed as a combination of membrane finite element and Bogner, Fox and Schmitt plate element.

Optimization Design of Coordinate Measuring Machine Based on ANSYS Software

2010 ◽  
Vol 42 ◽  
pp. 453-456
Author(s):  
Yong Gang Yan ◽  
Yan Qin Li ◽  
Zhan Kui Wang
Keyword(s):  
Optimization Design ◽  
Large Scale ◽  
High Efficiency ◽  
Design Method ◽  
Three Dimensional ◽  
Coordinate Measuring Machine ◽  
National Defense ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Measuring Machine

Coordinate measuring machine (CMM) is a large-scale geometrical detecting instrument. It is of high accuracy, high efficiency simple operation and automation. So, it can ensure the product quality for modern mechanical manufacture industry, and is widely used in the industry such as aircraft, automobile, military and national defense. However, it does not meet gradually the requirement of modern industry because of its measuring accuracy. How to monitor geometrical error rapidly and high accurately is a key research project. To solve the problem, some studies have been carried out. In this paper, a coordinate measuring machine was firstly designed by modern design method. Three dimensional model is built using PRO/E software. And some key components were optimized by using finite element analysis method. The simulating results show that the size and structure of the designed coordinate measuring machines are optimized and improved relate to previous CMM. This study will play an important instructing role for us in studying a novel CMM.

Free Vibration Analysis of Frame Structures Using BSWI Method

2008 ◽  
Author(s):  
Farhang Daneshmand ◽  
Abdolaziz Abdollahi ◽  
Mehdi Liaghat ◽  
Yousef Bazargan Lari
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Vibration Analysis ◽  
Degrees Of Freedom ◽  
Frame Structures ◽  
Shape Functions ◽  
Element Analysis ◽  
B Spline ◽  
Multi Level ◽  
Element Method

Vibration analysis for complicated structures, or for problems requiring large numbers of modes, always requires fine meshing or using higher order polynomials as shape functions in conventional finite element analysis. Since it is hard to predict the vibration mode a priori for a complex structure, a uniform fine mesh is generally used which wastes a lot of degrees of freedom to explore some local modes. By the present wavelets element approach, the structural vibration can be analyzed by coarse mesh first and the results can be improved adaptively by multi-level refining the required parts of the model. This will provide accurate data with less degrees of freedom and computation. The scaling functions of B-spline wavelet on the interval (BSWI) as trial functions that combines the versatility of the finite element method with the accuracy of B-spline functions approximation and the multiresolution strategy of wavelets is used for frame structures vibration analysis. Instead of traditional polynomial interpolation, scaling functions at the certain scale have been adopted to form the shape functions and construct wavelet-based elements. Unlike the process of wavelets added directly in the other wavelet numerical methods, the element displacement field represented by the coefficients of wavelets expansions is transformed from wavelet space to physical space via the corresponding transformation matrix. To verify the proposed method, the vibrations of a cantilever beam and a plane structures are studied in the present paper. The analyses and results of these problems display the multi-level procedure and wavelet local improvement. The formulation process is as simple as the conventional finite element method except including transfer matrices to compute the coupled effect between different resolution levels. This advantage makes the method more competitive for adaptive finite element analysis. The results also show good agreement with those obtained from the classical finite element method and analytical solutions.

scholarly journals Large scale simulation of pressure induced phase-field fracture propagation using Utopia

2021 ◽  
Author(s):  
Patrick Zulian ◽  
Alena Kopaničáková ◽  
Maria Giuseppina Chiara Nestola ◽  
Andreas Fink ◽  
Nur Aiman Fadel ◽  
...  
Keyword(s):  
Phase Field ◽  
Large Scale ◽  
Parallel Implementation ◽  
Fracture Propagation ◽  
Trust Region ◽  
Fracture Networks ◽  
Parallel Solution ◽  
Level Data ◽  
Non Linear ◽  
High Level

AbstractNon-linear phase field models are increasingly used for the simulation of fracture propagation problems. The numerical simulation of fracture networks of realistic size requires the efficient parallel solution of large coupled non-linear systems. Although in principle efficient iterative multi-level methods for these types of problems are available, they are not widely used in practice due to the complexity of their parallel implementation. Here, we present Utopia, which is an open-source C++ library for parallel non-linear multilevel solution strategies. Utopia provides the advantages of high-level programming interfaces while at the same time a framework to access low-level data-structures without breaking code encapsulation. Complex numerical procedures can be expressed with few lines of code, and evaluated by different implementations, libraries, or computing hardware. In this paper, we investigate the parallel performance of our implementation of the recursive multilevel trust-region (RMTR) method based on the Utopia library. RMTR is a globally convergent multilevel solution strategy designed to solve non-convex constrained minimization problems. In particular, we solve pressure-induced phase-field fracture propagation in large and complex fracture networks. Solving such problems is deemed challenging even for a few fractures, however, here we are considering networks of realistic size with up to 1000 fractures.

scholarly journals Scalable Hierarchical Parallel Algorithm for the Solution of Super Large-Scale Sparse Linear Equations

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Ran Xu ◽  
Bin Liu ◽  
Yuan Dong
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Linear Equations ◽  
Element Analysis ◽  
Accuracy Requirement ◽  
Triangle Lattice ◽  
Slave Processor ◽  
Global Equilibrium ◽  
High Scalability ◽  
Local Relaxation

The parallel linear equations solver capable of effectively using 1000+ processors becomes the bottleneck of large-scale implicit engineering simulations. In this paper, we present a new hierarchical parallel master-slave-structural iterative algorithm for the solution of super large-scale sparse linear equations in a distributed memory computer cluster. Through alternatively performing global equilibrium computation and local relaxation, the specific accuracy requirement can be met in a few iterations. Moreover, each set/slave-processor majorly communicates with its nearest neighbors, and the transferring data between sets/slave-processors and the master-processor is always far below the communication between neighboring sets/slave-processors. The corresponding algorithm for implicit finite element analysis has been implemented based on the MPI library, and a super large 2-dimension square system of triangle-lattice truss structure under randomly distributed loadings is simulated with over 1 × 109 degrees of freedom (DOF) on up to 2001 processors of the “Exploration 100” cluster in Tsinghua University. The numerical experiments demonstrate that this algorithm has excellent parallel efficiency and high scalability, and it may have broad applications in other implicit simulations.

Boundary Condition Related Mixed Boundary Element and its Application in FMBEM for 3D Elastostatic Problem

2015 ◽  
Vol 12 (05) ◽  
pp. 1550029 ◽  
Author(s):  
Yingjun Wang ◽  
Xiaowei Deng ◽  
Qifu Wang ◽  
Zhaohui Xia ◽  
Hua Xu
Keyword(s):  
Boundary Condition ◽  
Boundary Element ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Mixed Boundary ◽  
Automatic Generation ◽  
Element Analysis ◽  
Triangular Elements ◽  
Boundary Element Analysis ◽  
Element Method

A boundary condition (BC) related mixed element method is presented to address the corner problem in boundary element method (BEM) for 3D elastostatic problems. In this method, noncontinuous elements (NCEs) are only used at the displacement-prescribed corners/edges and continuous elements (CEs) in other places, which can decrease the degrees of freedom (DOFs) compared to the approach using NCEs at all corners/edges. Moreover, an automatic generation algorithm of BC related mixed linear triangular elements is implemented with the help of 3D modeling engine ACIS, and the boundary element analysis (BEA) is integrated into CAD systems. In order to solve large scale problems, the fast multipole BEM (FMBEM) with mixed elements is proposed and utilized in the BEA. The examples show that the node shift scheme adopting 1/4 is optimal and the BEM/FMBEM using mixed elements can produce more accurate results by only increasing a small number of DOFs.

A Logarithmic Complexity Divide and Conquer Algorithm for Flexible Multibody Dynamics

2005 ◽  
Author(s):  
Rudranarayan Mukherjee ◽  
Kurt Anderson
Keyword(s):  
Elastic Deformation ◽  
Degrees Of Freedom ◽  
Parallel Implementation ◽  
Equations Of Motion ◽  
Computational Cost ◽  
Flexible Multibody Dynamics ◽  
Divide And Conquer ◽  
Element Analysis ◽  
Large Rotations ◽  
Nonlinear Equations Of Motion

This paper presents an efficient algorithm for parallel implementation of multi-flexible-body dynamics systems simulation and analysis. The effective overall computational cost of the algorithm is logarithmic when implemented with a processor optimal O(n) processors. This algorithm formulates and solves the nonlinear equations of motion for mechanical systems with interconnected flexible bodies subject to small elastic deformation together with large rotations and translations. The large rotations or translations are modeled as rigid body degree of freedom associated with the interconnecting kinematic joint degrees of freedom. The elastic deformation of the component bodies is modeled through the use of admissible shape functions generated using standard finite element analysis software or otherwise. Apart from the approximation associated with the elastic deformations, this algorithm is exact, non-iterative and applicable to generalized multi-flexible chain and free topologies.

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