Dynamic Simulation of Freight Car and Lading During Impact

1977 ◽  
Vol 99 (4) ◽  
pp. 859-866 ◽  
Author(s):  
P. V. Kasbekar ◽  
V. K. Garg ◽  
G. C. Martin
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Parametric Study ◽  
Degrees Of Freedom ◽  
Impact Damage ◽  
Packaging Materials ◽  
Freight Car ◽  
Three Degrees Of Freedom

A dynamic analysis is presented to explain damage to railroad cars and ladings resulting from impacts. In the analysis, a mathematical model consisting of the car body and freight in the car is presented. Each freight element assumes three degrees of freedom for the computer simulation. A parametric study is made to establish sensitivity of car parameters and impact conditions. The study should be useful to aid in finding means for controlling impact damage and in designing packaging materials.

Accelerometer correction for the dynamic analysis of damped multi-degree of freedom systems

1969 ◽  
Vol 59 (4) ◽  
pp. 1591-1598
Author(s):  
G. A. McLennan
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Exact Method ◽  
Three Degrees Of Freedom

Abstract An exact method is developed to eliminate the accelerometer error in dynamic response calculations for damped multi-degree of freedom systems. It is shown that the exact responses of a system can be obtained from the approximate responses which are conventionally calculated from an accelerogram. Response calculations were performed for two typical systems with three degrees of freedom for an assumed pseudo-earthquake. The results showed that the approximate responses may contain large errors, and that the correction developed effectively eliminates these errors.

Finite Element Analysis of 2-D Structures by New Strain Based Triangular Element

2018 ◽  
Vol 35 (3) ◽  
pp. 305-313 ◽  
Author(s):  
C. Rebiai
Keyword(s):  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Numerical Solutions ◽  
Time Integration ◽  
Triangular Element ◽  
Membrane Element ◽  
Lumped Mass ◽  
Element Analysis ◽  
Benchmark Tests ◽  
Three Degrees Of Freedom

ABSTRACTIn this investigation, a new simple triangular strain based membrane element with drilling rotation for 2-D structures analysis is proposed. This new numerical model can be used for linear and dynamic analysis. The triangular element is named SBTE and it has three nodes with three degrees of freedom at each node. The displacements field of this element is based on the assumed functions for the various strains satisfying the compatibility equations. This developed element passed both patch and benchmark tests in the case of bending and shear problems. For the dynamic analysis, lumped mass with implicit/explicit time integration are employed. The obtained numerical results using the developed element converge toward the analytical and numerical solutions in both analyses.

Thermogasodynamic Analysis of the Segmented Annular Seal

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
Samia Dahite ◽  
Mihai Arghir
Keyword(s):  
Parametric Study ◽  
Thermal Effects ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Leading Edge ◽  
Test Case ◽  
Isothermal Model ◽  
Pocket Depth ◽  
Annular Seal ◽  
Three Degrees Of Freedom

Abstract The present work deals with the thermogasodynamic analysis of the segmented annular seal provided with Rayleigh pockets. The paper is a continuation of the work presented Arghir, M., and Mariot, A. (2017, “Theoretical Analysis of the Static Characteristics of the Carbon Segmented Seal,” ASME J. Tribol., 139(6), p. 062202.) where an isothermal model of the segmented annular seal was first presented. Each segment had three degrees-of-freedom, and its static position was obtained by solving the nonlinear equations of equilibrium. Thermal effects are now introduced by considering a simplified form of the energy equation in the thin gas film coupled with the three dimensional heat transfer in a segment of the seal and in the rotor. An efficient numerical algorithm is developed. A parametric study was performed for a segmented annular seal with pockets taken from the literature and operating with air. First, a test case proved the necessity of considering three degrees-of-freedom for the segment and not only its radial displacement. The parametric study was then performed for two different pocket depths, two pressure differences, and different rotation speeds. The results showed a non-uniform heating with larger temperatures at the leading edge of the segment where the minimal film thickness occurs. Heating is proportional to the pocket depth that lowers the lift force of the segment and to the pressure difference that closes the seal.

Improved Positioning of Pneumatic Cylinder by Using Flexible Coupling between the Piston and Rod

1992 ◽  
Vol 206 (6) ◽  
pp. 431-435 ◽  
Author(s):  
G V Krejnin ◽  
I L Krivz ◽  
L A Smelov
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Parameter Optimization ◽  
Degrees Of Freedom ◽  
Control Parameter ◽  
Pneumatic Cylinder ◽  
Output Link ◽  
Positioning Accuracy ◽  
Flexible Coupling ◽  
And Control

Positioning accuracy of a pneumatic piston drive with flexible coupling between the piston and rod is considered. Improved positioning was expected due to the fact that the rod friction is usually considerably less than the piston friction. When the piston stops under the action of its friction force the rod continues the motion, providing the precision positioning of the output link. A mathematical model of a positioning pneumatic piston drive with two degrees of freedom was generated. Computer simulation of the performance of short and long strokes showed the feasibility of the improved positioning which provided design and control parameter optimization.

Numerical Analysis of the Grasp Configuration of a Planar 3-DOF Linkage-Driven Underactuated Finger

2012 ◽  
Vol 8 (2) ◽  
Author(s):  
Hamed Khakpour ◽  
Lionel Birglen
Keyword(s):  
Numerical Analysis ◽  
Dynamic Simulation ◽  
Degrees Of Freedom ◽  
Joint Angles ◽  
Final Configuration ◽  
Contact Points ◽  
Novel Method ◽  
Three Degrees Of Freedom ◽  
Underactuated Finger ◽  
Simulation Package

This paper proposes a novel method to investigate the grasp sequence of an underactuated (a.k.a. adaptive) finger with three degrees of freedom but only one actuator and find its final configuration. This method considers the magnitude and the sign of the torques generated on the phalanges of the finger through the contact points. By using these torques as indices, the algorithm calculates the values of the joint angles during the grasping sequence until the finger reaches its final configuration. To illustrate the effectiveness of this method a class of a 3-DOF adaptive finger is chosen and analyzed and then, using the proposed methodology, its grasp configuration is calculated when grasping different fixed objects. Finally, simulations are repeated using a dynamic simulation package and the obtained results are compared to the proposed method. The results show that the method can properly estimate the final configuration of the grasp.

Digital Computer Simulation of Railroad Freight Car Rocking

1968 ◽  
Vol 90 (4) ◽  
pp. 701-706 ◽  
Author(s):  
A. A. Liepins
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Computer Program ◽  
Digital Computer ◽  
Test Results ◽  
Model Response ◽  
Freight Car ◽  
Railroad Freight

A mathematical model for the simulation of railroad freight car rocking is presented. The equations of the model are developed into a digital computer program. The model response is validated by two series of test results, and the model is considered reliable for engineering predictions.

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