Definition of Boundary Conditions and Dynamic Analysis of Rocket Sled and Turntable

2011 ◽  
Vol 52-54 ◽  
pp. 261-266 ◽  
Author(s):  
Jian Hua Zhang ◽  
Shou Shan Jiang

The Dynamics Analysis & Simulation of the Rocket Sled were done based on the Multibody System Dynamics and Finite Element Analysis Theory. The most difficult work in the analysis is how to establish the boundary conditions of the rocket sled. This paper makes this kind of attempt. Then the relevant postprocessing figures and data were obtained,thereby providing the designer and manufacturer with detailed and reliable data. The conclusion is the simulation method is more effective than those before and the boundary conditions are acceptable.

2011 ◽  
Vol 346 ◽  
pp. 447-454
Author(s):  
Jian Hua Zhang ◽  
Shou Shan Jiang

The Dynamics Analysis & Simulation of the Rocket Sled were done based on Multibody System Dynamics and Finite Element Analysis Theory. The most difficult work in the analysis was establishing the boundary conditions of the rocket sled. The paper made this kind of attempt. Then the relevant post processing figures and data were obtained, thereby providing the designer and manufacturer with detailed and reliable data. The conclusion is the simulation method is more effective than those before and the boundary conditions is correct and acceptable.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1388
Author(s):  
Daniele Oboe ◽  
Luca Colombo ◽  
Claudio Sbarufatti ◽  
Marco Giglio

The inverse Finite Element Method (iFEM) is receiving more attention for shape sensing due to its independence from the material properties and the external load. However, a proper definition of the model geometry with its boundary conditions is required, together with the acquisition of the structure’s strain field with optimized sensor networks. The iFEM model definition is not trivial in the case of complex structures, in particular, if sensors are not applied on the whole structure allowing just a partial definition of the input strain field. To overcome this issue, this research proposes a simplified iFEM model in which the geometrical complexity is reduced and boundary conditions are tuned with the superimposition of the effects to behave as the real structure. The procedure is assessed for a complex aeronautical structure, where the reference displacement field is first computed in a numerical framework with input strains coming from a direct finite element analysis, confirming the effectiveness of the iFEM based on a simplified geometry. Finally, the model is fed with experimentally acquired strain measurements and the performance of the method is assessed in presence of a high level of uncertainty.


Author(s):  
Giuseppe Catania ◽  
Silvio Sorrentino

In the Rayleigh-Ritz condensation method the solution of the equation of motion is approximated by a linear combination of shape-functions selected among appropriate sets. Extensive literature dealing with the choice of appropriate basis of shape functions exists, the selection depending on the particular boundary conditions of the structure considered. This paper is aimed at investigating the possibility of adopting a set of eigenfunctions evaluated from a simple stucture as a general basis for the analysis of arbitrary-shaped plates. The results are compared to those available in the literature and using standard finite element analysis.


2012 ◽  
Vol 271-272 ◽  
pp. 705-709
Author(s):  
Hong Jiang Chen ◽  
Yue Hai Wu

Space grid structure of modern large span structure engineering in the most commonly used structure form. This paper used ANSYS network space truss finite element analysis, discuss the element type, and the selection of material models, and the definition of the limit stress, when necessary, even considering the bar buckling state ( buckling ). Under various load (permanent loads, wind loads, seismic loads, under the action of gravity ), using the powerful finite element analysis software ANSYS on the structure static analysis, after the use of ANSYS powerful optimization design function, the structure safety, the bar section optimization design, and then on the basis of the existing rod a cross section, a reasonable choice of bar section, reduce the material consumption, to achieve the best economic, reasonable design, implementation can develop continuously, make the satisfactory design.


Author(s):  
V. Devaraja Holla ◽  
S. S. Krishnan ◽  
B. Gurumoorthy

Abstract This paper describes an algorithm for the construction of solid model from measured point data using Convex Partitioning approach. Convex Partitioning approach is based on the idea that any non-convex body can be viewed as a combination of several convex pieces. The input constitutes a set or cluster of points, measured on each face of the object, which is obtained by scanning the part. Points in each cluster are used to fit a plane or a non-planar surface depending upon the type of face. Partitioning is done along the planes till one gets all the convex pieces. The individual convex pieces are then combined together to get the final model of the object. The definition of convex partition is relaxed for objects having curved faces, to be an object with all its edges convex. Apart from allowing the construction of solid model from measured point data, the output (convex pieces) obtained from this approach is useful in planning for rapid prototyping and feature suppression in finite element analysis.


2014 ◽  
Vol 602-605 ◽  
pp. 1594-1597
Author(s):  
Han Xin Chen ◽  
Shi Qi Yang

This paper investigated the ultrasonic mechanism of Time of Flight Diffraction (TOFD) by finite element analysis for the better applications of ultrasonic TOFD (Time of Flight Diffraction) detection technology. The welding steel plate with the artificial defects is used in the finite element analysis model. The experimental A-scan signal with higher noise is filtered by the wavelet transform, which can clearly show defective diffracted wave. The software simulation of ultrasound is used to present the propagation process of ultrasonic signal inside the sample. Simulation results are compared with the experimental results, which shows valid basis for the practical TOFD ultrasonic detection methods in industrial applications.


Author(s):  
Shivdayal Patel ◽  
B. P. Patel ◽  
Suhail Ahmad

Welding is one of the most used joining methods in the ship industry. However, residual stresses are induced in the welded joints due to the rapid heating and cooling leading to inhomogenously distributed dimensional changes and non-uniform plastic and thermal strains. A number of factors, such as welding speed, boundary conditions, weld geometry, weld thickness, welding current/voltage, number of weld passes, pre-/post-heating etc, influence the residual stress distribution. The main aim of this work is to estimate the residual stresses in welded joints through finite element analysis and to investigate the effects of boundary conditions, welding speed and plate thickness on through the thickness/surface distributions of residual stresses. The welding process is simulated using 3D Finite element model in ABAQUS FE software in two steps: 1. Transient thermal analysis and 2. Quasi-static thermo-elasto-plastic analysis. The normal residual stresses along and across the weld in the weld tow region are found to be significant with nonlinear distribution. The residual stresses increase with the increase in the thickness of the plates being welded. The nature of the normal residual stress along the weld is found to be tensile-compressive-tensile and the nature of normal residual stress across the weld is found to be tensile along the thickness direction.


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