Dynamic Analysis of Handling Compliant Sheet-Metal Blanks

2007 ◽  
Author(s):  
Gene Y. Liao
Keyword(s):  
Sheet Metal ◽  
Stiffness Matrix ◽  
Material Handling ◽  
Equations Of Motion ◽  
Time Integration ◽  
Nonlinear Finite Element ◽  
Time Varying ◽  
End Effector ◽  
Part Quality ◽  
Element Technique

Automating material handling of flexible sheet-metal blanks in stamping process requires attention due to its significant impact on product quality and productivity. This paper investigated the capability of a fully dynamic and nonlinear finite element technique in developing virtual material handling process of compliant sheet-metal blanks subject to time varying movability conditions. The technique used explicit time integration to avoid the formulation of stiffness matrix by a direct integration of the equations of motion. The influence of holding end-effector layout scheme and movability conditions on the final part quality was investigated.

DYNAMICS OF SHALLOW CABLES UNDER TURBULENT WIND: A NONLINEAR FINITE ELEMENT APPROACH

2011 ◽  
Vol 11 (04) ◽  
pp. 755-774 ◽  
Author(s):  
NICOLA IMPOLLONIA ◽  
GIUSEPPE RICCIARDI ◽  
FERNANDO SAITTA
Keyword(s):  
Finite Element ◽  
Equilibrium Shape ◽  
Equations Of Motion ◽  
Plane Motion ◽  
Computational Effort ◽  
Nonlinear Finite Element ◽  
Initial Shape ◽  
Linear Behavior ◽  
Element Technique ◽  
Nonlinear Equations Of Motion

In classic cable theory, vibrations are usually analyzed by writing the equations of motion in the neighborhood of the initial equilibrium configuration. Furthermore, a fundamental difference exists between out-of-plane motions, which basically corresponds to the linear behavior of a taut string and in-plane motion, where self-weight determines a sagged initial profile. This work makes use of a continuous approach to establish the initial shape of the cable when it is subjected to wind or fluid flow arbitrarily directed and employed a novel nonlinear finite element technique in order to investigate the dynamics present around the initial equilibrium shape of the cable. Stochastic solutions in the frequency domain are derived for a wind-exposed cable after linearization of the problem. By applying the proper orthogonal decomposition (POD) technique with the aim of reducing computational effort, an approach to simulate modal wind forces is proposed and applied to the nonlinear equations of motion.

Modeling and Optimization of End Effector Layout for Handling Compliant Sheet Metal Parts

2000 ◽  
Vol 123 (3) ◽  
pp. 473-480 ◽  
Author(s):  
D. Ceglarek ◽  
H. F. Li ◽  
Y. Tang
Keyword(s):  
Sheet Metal ◽  
Material Handling ◽  
Design Stage ◽  
End Effector ◽  
Industrial Practice ◽  
Modeling And Optimization ◽  
Sheet Metal Stamping ◽  
Sheet Metal Parts ◽  
Metal Stamping ◽  
Compliant Parts

Material handling of compliant parts is one of the most critical and underresearched problems in the sheet metal stamping industry. The fundamental shortcoming of currently studied material handling systems for sheet metal stamping is the lack of analysis of its impact on part dimensional quality and production throughput. This paper addresses this problem by development of a generic methodology for modeling and optimization of part holding end-effector layout in order to minimize part dimensional deformation during handling operations. The methodology extends the design of “N-2-1” fixturing layout by adding part movability conditions. It considers part CAD model, handling direction and motion kinematic parameters to determine the best end effector layout. This methodology is realized by integrating FEM part and loading modeling with the optimization algorithm. It can be implemented into the design stage of a stamping line so that the trial and error process, which is current industrial practice, can be greatly shortened and the production throughput increased. Experimental results verify the proposed part holding end-effector layout methodology.

Modeling and Optimization of Fixture for Handling Compliant Sheet Metal Parts

1999 ◽  
Author(s):  
D. Ceglarek ◽  
H. F. Li ◽  
Y. Tang
Keyword(s):  
Sheet Metal ◽  
Material Handling ◽  
Design Stage ◽  
End Effector ◽  
Industrial Practice ◽  
Modeling And Optimization ◽  
Sheet Metal Stamping ◽  
Sheet Metal Parts ◽  
Metal Stamping ◽  
Compliant Parts

Abstract Material handling of compliant parts is one of the most critical and underresearched problems in the sheet metal stamping industry. The fundamental shortcoming of currently studied material handling systems for sheet metal stamping is the lack of analysis of its impact on part dimensional quality and production throughput. This paper addresses this problem by development of a generic methodology for modeling and optimization of part holding end-effector fixture layout in order to minimize part dimensional deformation during handling operations. The methodology extends the design of “N-2-1” fixturing layout by adding part movability conditions. It considers part CAD model, handling direction and motion kinematic parameters to determine the best end effector layout. This methodology is realized by integrating FEM part and loading modeling with the optimization algorithm. It can be implemented into the design stage of a stamping line so that the trial and error process, which is current industrial practice, can be greatly shortened and the production throughput increased. Experimental results verify the proposed part holding end-effector layout methodology.

Metric Damping of MDOF Systems in High Transient Motion

2005 ◽  
Vol 128 (1) ◽  
pp. 50-55 ◽  
Author(s):  
A. Al Majid ◽  
A. Allezy ◽  
R. Dufour
Keyword(s):  
Variational Problem ◽  
Transient Response ◽  
Riemannian Space ◽  
Equations Of Motion ◽  
Time Integration ◽  
Degree Of Freedom ◽  
Time Varying ◽  
Transient Motion ◽  
Additional Dimension ◽  
Mdof Systems

This paper deals with damping due to transient motion in the case of multi-degree-of-freedom (MDOF) system. The main aim of this research is to make the method presented by the authors in a previous paper available for MDOF systems. An method based on relativity concepts is developed in order to identify and evaluate a metric damping due to time-varying forcing frequency. An additional dimension for each degree of freedom (DOF) is introduced. The variational problem of the metric of a Riemannian space gives the geodesic equations, i.e., equations of motion that, after time integration carried out with several types of numerical schemes, permit one to predict the forced transient response of a 3-DOF system. The proposed metric approach makes the experimental results correspond with the simulated results.

Metric Damping of MDOF Systems in High Transient Motion

2003 ◽  
Author(s):  
A. Al Majid ◽  
A. Allezy ◽  
R. Dufour
Keyword(s):  
Transient Response ◽  
Riemannian Space ◽  
Equations Of Motion ◽  
Time Integration ◽  
Original Method ◽  
Degree Of Freedom ◽  
Time Varying ◽  
Transient Motion ◽  
Additional Dimension ◽  
Mdof Systems

This article deals with damping due to transient motion in the case of a Multi-Degree-Of-Freedom (MDOF) system. The main aim of this research is to make the method presented in a previous article by the authors available for MDOF systems. An original method based on relativity concepts is developed in order to identify, prove and evaluate a metric damping due to time-varying forcing frequencies. An additional dimension for each Degree-Of-Freedom (DOF) is introduced. The variational problem of the metric of a Riemannian space gives the geodesic equations, i.e. equations of motion which, after time integration is carried out with several types of numerical schemes, permits predicting the forced transient response of a 3-DOF system. The proposed metric approach is validated experimentally.

A Dexterous Part-Holding Model for Handling Compliant Sheet Metal Parts

2001 ◽  
Vol 124 (1) ◽  
pp. 109-118 ◽  
Author(s):  
H. F. Li ◽  
D. Ceglarek ◽  
Jianjun Shi
Keyword(s):  
Production Rate ◽  
Sheet Metal ◽  
Material Handling ◽  
Experimental Studies ◽  
Model Parameters ◽  
Element Analysis ◽  
End Effector ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
End Effectors

Material handling of compliant sheet metal parts significantly impacts both part dimensional quality and production rate in the stamping industry. This paper advances previously developed material handling end effector layout optimization methodology for rigid point end effectors [1] by developing a dexterous part-holding end effector model. This model overcomes the shortcomings of the rigid point part-holding end effector model by predicting part deformation more accurately for various modes of deformation and for a set of part-holding end effector locations. This is especially important for handling systems which utilize vacuum cup end effectors widely used for handling of large sheet metal parts. The dexterous end effector model design method and an algorithm for estimation of model parameters are developed. The algorithm combines data from design of computer simulations and from the set of experiments by integrating finite element analysis and a statistical data processing technique. Experimental studies are conducted to verify the developed model and the model parameter estimation algorithm. The developed methodology provides an analytical tool for product and process designers to accurately predict part deformation during handling, which further leads to minimization of part deformation, improvement of part dimensional quality and increase of production rate.

Time Integration Incorporated Sensitivity Analysis With Generalized-α Method for Multibody Dynamics Systems

2011 ◽  
Author(s):  
Guang Dong ◽  
Zheng-Dong Ma ◽  
Gregory Hulbert ◽  
Noboru Kikuchi
Keyword(s):  
Sensitivity Analysis ◽  
Topology Optimization ◽  
Dynamic Loading ◽  
Multibody Dynamics ◽  
Equations Of Motion ◽  
Time Integration ◽  
Optimization Method ◽  
Sensitivity Analysis Method ◽  
System Equations ◽  
Consecutive Time

The topology optimization method is extended for the optimization of geometrically nonlinear, time-dependent multibody dynamics systems undergoing nonlinear responses. In particular, this paper focuses on sensitivity analysis methods for topology optimization of general multibody dynamics systems, which include large displacements and rotations and dynamic loading. The generalized-α method is employed to solve the multibody dynamics system equations of motion. The developed time integration incorporated sensitivity analysis method is based on a linear approximation of two consecutive time steps, such that the generalized-α method is only applied once in the time integration of the equations of motion. This approach significantly reduces the computational costs associated with sensitivity analysis. To show the effectiveness of the developed procedures, topology optimization of a ground structure embedded in a planar multibody dynamics system under dynamic loading is presented.

On a sphere performing linear and torsional oscillations in a viscous fluid

1988 ◽  
Vol 66 (7) ◽  
pp. 576-579
Author(s):  
G. T. Karahalios ◽  
C. Sfetsos
Keyword(s):  
Boundary Layer ◽  
Viscous Fluid ◽  
Secondary Flow ◽  
Small Amplitude ◽  
Equations Of Motion ◽  
Successive Approximations ◽  
Method Of Successive Approximations ◽  
Time Varying ◽  
Torsional Oscillations

A sphere executes small-amplitude linear and torsional oscillations in a fluid at rest. The equations of motion of the fluid are solved by the method of successive approximations. Outside the boundary layer, a steady secondary flow is induced in addition to the time-varying motion.

A Critical Review of Tube and Sheet Metal Hydroforming Technology

1996 ◽  
Author(s):  
Jian An ◽  
A. H. Soni
Keyword(s):  
Sheet Metal ◽  
Thickness Distribution ◽  
Fluid Pressure ◽  
Point Of View ◽  
Parameter Design ◽  
Back Side ◽  
Part Quality ◽  
Element Simulation ◽  
Part Surface ◽  
Hydroforming Process

Abstract The hydroforming technology, which is rapidly gaining popularity in the sheet metal and tube forming industry is reviewed. The features and the characteristics of the hydroforming process are described. The uniformly distributed fluid pressure covers the back side of the sheet as a die generates many advantages in the technical point of view as improving the part surface quality, reducing the forming severity and smoothing the thickness distribution. The benefits of using hydroforming technology are examined and analyzed in a technical level. The better part quality, less cost of tooling, materials saving and part weight reduction can be achieved using the hydroforming technology. The design methodologies for the hydroforming process parameters are reviewed and discussed in a certain detail. Computer-aided-engineering such as finite element simulation is suggested for such process parameter design.

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