Modal Based Geometric Stiffening Formulation for Dynamics Simulation of Multibody Systems

2011 ◽  
Author(s):  
Fengxia Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Dynamics Simulation ◽  
Reduced Model ◽  
Reduced Models ◽  
Modal Reduction ◽  
Body Dynamics ◽  
Geometric Stiffening ◽  
Multi Body

This work concerns the implementation of nonlinear modal reduction to flexible multi-body dynamics. Linear elastic theory will lead to instability issues with rotating beamlike structures, due to the neglecting of the membrane-bending coupling on the beam cross-section. During the past decade, considerable efforts have been focused on the derivation of geometric nonlinear formulation based on nodal coordinates. In this work, in order to improve the convergence characteristic and also to reduce the computation time in flexible multi-body dynamics, which is extremely important for complicated large systems, a standard modal reduction procedure based on matrix operation is developed with essential geometric stiffening nonlinearities retained in the equation of motion. The example used in this work is a rotating Euler-Bernoulli beam, two nonlinear reduced models were established based on modal coordinates, the first reduced model created from theoretical bending and axial mode shapes by Galerkin method; the second reduced model is derived by the standard matrix operator from a full finite element model. Transient simulation results of lower degrees of freedom from above two reduced models are compared with those obtained from full nonlinear finite element model.

MODEL REDUCTION WITH GEOMETRIC STIFFENING NONLINEARITIES FOR DYNAMIC SIMULATIONS OF MULTIBODY SYSTEMS

2013 ◽  
Vol 13 (08) ◽  
pp. 1350046 ◽  
Author(s):  
FENGXIA WANG
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Reduction ◽  
Reduction Process ◽  
Flexible Multibody Dynamics ◽  
Element Model ◽  
Reduced Model ◽  
Matrix Operation ◽  
Reduced Models ◽  
Geometric Stiffening

This work investigates the implementation of nonlinear model reduction to flexible multibody dynamics. Linear elastic theory will lead to instability issues with rotating beam-like structures, due to the neglecting of the membrane-bending coupling on the beam cross-section. During the past decade, considerable efforts have been focused on the derivation of geometric nonlinear formulation based on nodal coordinates. In order to reduce the computation cost in flexible multibody dynamics, which is extremely important for complex large system simulations, modal reduction is usually implemented to a rotating flexible structure with geometric nonlinearities retained in the model. In this work, a standard model reduction process based on matrix operation is developed, and the essential geometric stiffening nonlinearities are retained in the reduced model. The time responses of a tip point on a rotating Euler–Bernoulli blade are calculated based on two nonlinear reduced models. The first reduced model is derived by the standard matrix operation from a full finite element model and the second reduced model is obtained via the Galerkin method. The matrix operation model reduction process is validated through the comparison of the simulation results obtained from these two different reduced models. An interesting phenomenon is observed in this work: In the nonlinear model, if only quadratic geometric stiffing term is retained, the two reduced models converge to the full finite element model with only one bending mode and two axial modes. While if both quadratic and cubic geometric stiffing terms are retained in the nonlinear equation, the modal-based reduced model will not converge to the finite element model unless all eigenmodes are retained, that is the reduced model has no degree of freedom reduction at all.

Study on Wheel-Rail Coupled Vibration of Metro with Co-Simulation of Finite Element Analysis and Multi-Body Dynamics Simulation

2015 ◽  
Vol 752-753 ◽  
pp. 636-641
Author(s):  
Wen Jing Sun ◽  
Dao Gong ◽  
Jin Song Zhou
Keyword(s):  
Finite Element ◽  
Dynamics Simulation ◽  
Track Structure ◽  
Coupled Vibration ◽  
Dynamics Model ◽  
Element Analysis ◽  
Modal Reduction ◽  
Body Dynamics ◽  
Flexible Track ◽  
Multi Body

Based on the multi-body dynamics theory and modal-reduction analysis, finite element method and multi-body dynamics were combined to establish the flexible track model. The rigid-flexible coupled dynamics model can reflect the features of coupled vibration accurately. When the flexibility of the rail, damping and stiffness of support layers under the rail are taken into consideration, the whole track structure acted as a buffer while wheel and rail is interacting with each other. Compared with rigid track model, the wheel-rail vibration is less in the flexible track model. The proposed method in this paper is simple and effective, which makes the calculation of vehicle-track dynamic response more convenient and quick.

Multi-body dynamics co-simulation of hoisting wire rope

2017 ◽  
Vol 53 (1) ◽  
pp. 36-45 ◽  
Author(s):  
Qing Huang ◽  
Zhi Li ◽  
Hong-qian Xue
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Analysis ◽  
Dynamic Model ◽  
Loading Condition ◽  
Element Model ◽  
Wire Rope ◽  
Body Dynamics ◽  
Hoisting System ◽  
Multi Body

As more wire ropes with complex construction are used in the hoisting system of a crane, it becomes more necessary to predict the risks of the hoisting operation. Especially the wire rope, dynamic analysis is required to manage the potential risk in advance. Thus, in this article, a co-simulation method based on multi-body dynamics and finite element method is proposed to determine the dynamic responses of a hoisting system and wire rope. We developed a dynamic model of hoisting system based on ADAMS/Cable to formulate the time history response of dynamic force on wire rope, which could be used as the loading condition in the posterior finite element model. A three-dimensional geometric model for the multi-layered strands wire rope with a construction of 1+7+7 / 7+14 wires is implemented in the finite element analysis software ABAQUS, and both static and dynamic analyses are presented. The static analysis result of force–strain relation is compared with several experiment data, and the finite element model is proved accurate and reliable. In the latter case, the force–time curves obtained by dynamic model are imported to finite element model as loading condition to accomplish dynamic analysis. The co-simulation results of hoisting wire rope’s behavior subjected to dynamic loading during the hoisting process are carried out and discussed. The stress distribution and stress spectrum of wire rope are obtained, and the results show that the most dangerous regions are the lateral side of wire rope, especially the contact area of two wires in strands.

Lightweight Design for a New Tracked Triangular Wheel Structure

2013 ◽  
Vol 744 ◽  
pp. 78-82
Author(s):  
Jun Wen Xing ◽  
Hong Wu Pu ◽  
Xiang Zheng Meng ◽  
Li Qun Bao
Keyword(s):  
Finite Element ◽  
Lightweight Design ◽  
Element Model ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Wheeled Vehicle ◽  
Body Dynamics ◽  
Dry Soil ◽  
Multi Body ◽  
Structure Properties

A new tracked triangular wheel structure was introduced. A whole tracked triangular wheeled vehicle model was built in multi-body dynamics simulation software RecurDyn, and its climbing obstacle performance on the dry soil road was simulated. The author put the simulation results as loading conditions of finite element model. Finite element calculation and lightweight design for tracked triangular wheel base frame were completed. The results showed that the weight of the base frame reduced by 69.8%, the structure properties of the base frame improved, and the lightweight design goal was achieved.

Modelling of Piezoceramic Patches for Actuator Placement Strategies

2014 ◽  
Author(s):  
Michael Rose
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Model ◽  
Electrical Coupling ◽  
Element Model ◽  
Dynamics Simulation ◽  
Tool Chain ◽  
Active Layers ◽  
Speed Up ◽  
Actuator Placement

Piezoceramic Patches are commonly used as actuator devices in smart structures if the induced forces are sufficient for the application. To model these devices in a structural dynamics simulation, a finite element model can be augmented by active layers. This needs a suitable element meshing, taking care of the actual shapes and positions of the active patches in use. If many different setups have to be evaluated, which is naturally the case for placement strategies for suitable actuator positions, this approach is quite cumbersome. To ease and speed up the augmentation of fixed finite element models with piezoceramic patches, so called modal correction methods have been successfully used in this context. These approximative methods avoid the remeshing and the reassembling of the underlying finite element model by adapting the modal description of the structural model with the mass, stiffness and electrical coupling effects of the applied patches. In this paper different aspects of this modelling approach are discussed especially for a tool chain to optimize patch locations in an ASAC simulation environment.

Control-Oriented Order Reduction of Finite Element Model

1993 ◽  
Vol 115 (4) ◽  
pp. 708-711 ◽  
Author(s):  
K. Harold Yae ◽  
Daniel J. Inman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Degrees Of Freedom ◽  
Control Design ◽  
Element Model ◽  
Reduced Model ◽  
State Variables ◽  
Dynamics Modeling ◽  
Element Analysis

In the dynamics modeling of a structure, finite element analysis employs reduction techniques, such as Guyan’s reduction, that remove some of the “insignificant” physical coordinates, that is, degrees of freedom at a node point. Despite such reduction, the resultant model is still too large for control design. This warrants further reduction as is frequently done in control design by approximating a large dynamical system with a fewer number of state variables. A problem, however, arises because a model usually undergoes, before being reduced, some form of coordinate transformations that destroy the physical meanings of the states. To correct such a problem, we developed a method that expresses a reduced model in terms of a subset of the original states. The proposed method starts with a dynamic model that is originated and reduced in finite element analysis. The model is then converted to a state-space form, and reduced further by the internal balancing method. At this stage, being in the balanced coordinate system, the states in the reduced model have no apparent resemblance to those of the original model. Through another coordinate transformation that is developed in this paper, however, this reduced model is expressed by a subset of the original states, so that the states in the reduced model can be related to the degrees of freedom of the nodes in the original finite element model.

Analysis of Crankshaft Fatigue Strength Based on Integrated Finite Element Model

2010 ◽  
Vol 44-47 ◽  
pp. 1558-1562 ◽  
Author(s):  
Xiao Ping Chen ◽  
Ru Fu Hu ◽  
Shu Hua Zheng
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fatigue Limit ◽  
Limit Load ◽  
Element Model ◽  
Response Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Complex Mechanical Systems ◽  
Multi Body

Aiming at the complex mechanical systems for the prediction of the fatigue limit load requirements, this paper examines the relationship among finite element analysis model and the performance models. And a finite element modeling method for fatigue analysis is proposed. The finite element model can support static, modal, fatigue, and multi-body dynamic response analysis in parallel and collaboration. This method helps improve the fatigue limit load analysis.

Simulation and Study on Ride Comfort of Articulated Dump Truck Based on Rigid-Flex Coupling

2014 ◽  
Vol 494-495 ◽  
pp. 55-58
Author(s):  
Jie Guo
Keyword(s):  
Finite Element ◽  
Ride Comfort ◽  
Dynamic Theory ◽  
Dynamics Simulation ◽  
Dump Truck ◽  
Body System ◽  
Finite Element Software ◽  
Body Dynamics ◽  
Set Up ◽  
Multi Body

For the poor ride comfort performance of the articulated dump truck, the dynamic model of ADT was built and its dynamic characteristics were also studied through finite element and multi-body system dynamic theory. According to the modal neutral file generated by finite element software with the flexible processing, the flexible coupling virtual prototyping model was set up for the multi-body dynamics simulation in ADAMS to obtain and analyze the data about the ADT ride comfort. This paper provided references for the design, redesign and optimization of the ADT.

Lifetime Computational Models of Rolling Bearings in a 1.5MW Wind Turbine’s Epicyclic Gearbox

2012 ◽  
Vol 490-495 ◽  
pp. 1076-1080
Author(s):  
Xin Tan ◽  
Yao Li ◽  
Jun Jie Yang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Computational Model ◽  
Dynamic Model ◽  
Computational Models ◽  
Element Model ◽  
Rolling Bearings ◽  
Load Distributions ◽  
Multi Body

This paper introduces a computational model for calculating the lifetime of rolling bearings in a 1.5MW wind turbine’s epicyclic gearbox. At first, a quasi-dynamic model is established to analyze the skidding of bearings and the skew of rollers. Then, the load distributions on raceways and inner rings of bearings are calculated using the quasi-dynamic model. Meanwhile, a multi-body finite element model established in RomaxWind software is utilized to simulate and analyze dynamics behaviors of the epicyclic gearbox including all bearings. The comparison of bearings’ lifetimes calculated with different methods shows that the quasi-dynamic model can obtain very close results as the multi-body finite element model obtains, but costs less time. Failures occurring on inner and outer rings, such as pitting, adhesion, are mainly resulted from the misalignment of inner rings and roller number on the skidding of bearings

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