scholarly journals Structural dynamic modification of circular disc using pre-stressed fields

2012 ◽  
Vol 51 (No. 3) ◽  
pp. 79-84
Author(s):  
M. Naď
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Structural Dynamic ◽  
Disc Surface ◽  
Structural Dynamic Modification ◽  
Dynamic Modification ◽  
Dynamical Properties

Dynamical properties of circular discs are investigated in this paper. One of the techniques of the disc modifications to achieve the required dynamic properties is to initiate pre-stress in disc plane. To obtain appropriate in-plane stress either roll-tensioning of disc surface or volume transformation of disc segment can be used. The role of in-plane stresses is assessed from the change in natural frequencies and modal shapes. The natural frequency characteristics for various rolling position and various rolling depth of the annulus are obtained by modal analysis using Finite Element Method (FEM).

Beam Element Structural Dynamics Modification Using Experimental Modal Rotational Data

1995 ◽  
Vol 117 (3A) ◽  
pp. 265-271 ◽  
Author(s):  
John A. Cafeo ◽  
Martin W. Trethewey ◽  
H. Joseph Sommer
Keyword(s):  
Finite Element ◽  
Cantilever Beam ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Structural Dynamic ◽  
Modal Data ◽  
Structural Dynamic Modification ◽  
Dynamic Modification ◽  
Rotational Degrees Of Freedom ◽  
Fixed Beam

Structural dynamic modification (SDM) of a fixed-free (cantilever) beam to convert it into a fixed-fixed beam with experimental modal data is presented. The SDM focuses on incorporating experimental rotational degrees-of-freedom (DOF) measured with a novel laser measurement technique. A cantilever beam is tested to develop the experimental modal database including rotational degrees of freedom. A modal database from a finite-element model also is developed for comparison. A structural dynamic modification, with both databases, is performed using a Bernoulli-Euler beam to ground the free end of the cantilever beam. The hardware is then modified and a second experimental modal analysis of the resulting fixed-fixed beam performed. A finite-element model of the fixed-fixed beam also was created. Comparison of results from these four tests are used to assess the effectiveness of SDM using experimental modal rotational data. The evaluation shows that provided high quality experimental rotational modal data can be acquired, SDM work with beam elements can be effective in yielding accurate results.

scholarly journals Research on the dynamics of railway car construction

2019 ◽  
Vol 20 (1-2) ◽  
pp. 142-146
Author(s):  
Jarosław Bednarz
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Model ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Structural Models ◽  
Transformation Model ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Modal Model

Nowadays, one of the basic criteria of the design of mechanical structures are dynamic properties of the object. They have a significant effect on the vibration, emitted noise, fatigue strength, controllability and stability of the structure. The structural models are most often use to describe the dynamics of the structures. These models are built in accordance with the principles of the finite element method . Structural model can be used to determine the modal model which is a collection of natural frequencies and corresponding mode shapes by an appropriate coordinate transformation model. The construction pro-cess is called the modal analysis . The article presented a method of conducting the experimental modal studies of railway car. The aim of the study was to identify the dynamic properties including the frequency and mode shapes of the object..

A Design Approach for the Systematic Improvement of Support Locations for Vibrating Circuit Cards

1993 ◽  
Vol 115 (1) ◽  
pp. 118-123 ◽  
Author(s):  
J. M. Pitarresi ◽  
A. V. Di Edwardo
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Search Algorithm ◽  
Fold Increase ◽  
Initial Guess ◽  
Structural Dynamic ◽  
Systematic Improvement ◽  
Structural Dynamic Modification ◽  
Dynamic Modification

This paper approaches the problem of improving an initial guess at support locations for a vibrating circuit card so as to increase the first natural frequency of the card. The finite element method and structural dynamic modification techniques are combined with a simple sequential search algorithm to systematically improve the location of point supports for a circuit card populated with components. It is found that the proposed methodology can be useful for determining the support locations of a circuit card so as to increase its fundamental natural frequency. A case study is presented in which the original support locations on an existing commercial power supply circuit card are systematically improved giving a better than two fold increase in the natural frequency. Additionally, finite element modeling approaches for determining the modal characteristics of a circuit card are compared with experimental results.

scholarly journals Natural Characteristics Analysis of Frame of 1780 Tandem Rolling Mill

2011 ◽  
Vol 2-3 ◽  
pp. 1014-1017
Author(s):  
De Chen Zhang ◽  
Yan Ping Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rolling Mill ◽  
Dynamic Method ◽  
Natural Frequencies ◽  
Rolling Process ◽  
Structural Dynamic ◽  
Characteristics Analysis ◽  
Natural Characteristics ◽  
Element Method

According to the vibration happened in rolling process of 1780 tandem rolling mill. Finite element method and structural dynamic method were used to analysis in this paper. The natural frequencies of the rack were calculated. The comparision between two methods were done. It was helpful for designing and reducing vibration of the rolling process.

Modeling and Simulation of Dynamic Property of Vehicle Frame Based on Finite Element Method

2013 ◽  
Vol 367 ◽  
pp. 118-121
Author(s):  
Sheng Li Kong
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modeling And Simulation ◽  
Working Conditions ◽  
Dynamic Property ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
High Accuracy ◽  
Beam Model ◽  
Shell Models

The dynamic property of vehicle frame directly affects the safety and comfort of whole vehicles. In order to fully understand the dynamic properties of vehicle frame, both finite element beam and shell models for vehicle frame are established and the natural frequencies of vehicle frame in free working conditions are obtained. The results from beam model and shell model have high accuracy. Those results can be helpful for improvement and optimization of the vehicle frames.

Experimental Modal Analysis and Dynamic Response Prediction of PC Boards With Surface Mount Electronic Components

1991 ◽  
Vol 113 (3) ◽  
pp. 244-249 ◽  
Author(s):  
Tin-Lup Wong ◽  
Karl K. Stevens ◽  
Gang Wang
Keyword(s):  
Dynamic Models ◽  
Natural Frequencies ◽  
Response Prediction ◽  
Modal Testing ◽  
Mode Shapes ◽  
Electronic Components ◽  
Structural Dynamic ◽  
Surface Mount ◽  
Structural Dynamic Modification ◽  
Dynamic Modification

Use of modal testing and structural dynamic modification techniques for prediction of the modal parameters of a PC board with a surface-mount component is described. Experimentally determined natural frequencies and mode shapes of a PC board with and without an added component are presented. Several simple dynamic models of the component are evaluated. Results obtained indicate that the component can sometimes be modeled as a point mass.

THE ROLE OF FINITE ELEMENT METHOD IN CIVIL ENGINEERING

2018 ◽  
Vol 5 (02) ◽  
Author(s):  
Er. Hardik Dhull
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Approximate Solution ◽  
Analytical Method ◽  
Civil Engineering ◽  
The Finite Element Method ◽  
Engineering Problems ◽  
Building Components ◽  
Element Method

The finite element method is a numerical method that is used to find solution of mathematical and engineering problems. It basically deals with partial differential equations. It is very complex for civil engineers to study various structures by using analytical method,so they prefer finite element methods over the analytical methods. As it is an approximate solution, therefore several limitationsare associated in the applicationsin civil engineering due to misinterpretationof analyst. Hence, the main aim of the paper is to study the finite element method in details along with the benefits and limitations of using this method in analysis of building components like beams, frames, trusses, slabs etc.

scholarly journals An Extended Finite Element Method (XFEM) Study on the Elastic T-Stress Evaluations for a Notch in a Pipe Steel Exposed to Internal Pressure

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 507
Author(s):  
K. Yakoubi ◽  
S. Montassir ◽  
Hassane Moustabchir ◽  
A. Elkhalfi ◽  
Catalin Iulian Pruncu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Extended Finite Element Method ◽  
Research Study ◽  
Extended Finite Element ◽  
T Stress ◽  
Cracked Structures ◽  
Element Method

The work investigates the importance of the K-T approach in the modelling of pressure cracked structures. T-stress is the constant in the second term of the Williams expression; it is often negligible, but recent literature has shown that there are cases where T-stress plays the role of opening the crack, also T-stress improves elastic modeling at the point of crack. In this research study, the most important effects of the T-stress are collected and analyzed. A numerical analysis was carried out by the extended finite element method (X-FEM) to analyze T-stress in an arc with external notch under internal pressure. The different stress method (SDM) is employed to calculate T-stress. Moreover, the influence of the geometry of the notch on the biaxiality is also examined. The biaxiality gave us a view on the initiation of the crack. The results are extended with a comparison to previous literature to validate the promising investigations.

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