Interval Finite Element Analysis of Structural Dynamic Problems

2015 ◽  
Vol 8 (2) ◽  
pp. 382-389 ◽  
Author(s):  
Naijia Xiao ◽  
Rafi L. Muhanna ◽  
Francesco Fedele ◽  
Robert L. Mullen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Problems ◽  
Element Analysis ◽  
Structural Dynamic

Improved Results in Structural Dynamic Calculations by Linking Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA)

1995 ◽  
Author(s):  
Ulrich Gabbert ◽  
Manfred Zehn ◽  
Friedrich Wahl
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Numerical Models ◽  
Mass Matrix ◽  
Computer Time ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Element Analysis ◽  
Structural Dynamic

Abstract The paper deals with improvements of accuracy of structural dynamic calculations by using both the advantages of Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA). The basis for such improvements are reasonable mechanical and numerical models and accurate frequency response measurements (eigenfrequencies and mode shapes). The paper deals first with reasons for and estimations of errors in numerical and experimental analysis. It can be shown by theory and experiment that neither FEA nor EMA models are unique, due to inevitable incompleteness of the mode shapes and eigenfrequencies from a vibration test. Verification and updating of FE models by linking FEA with EMA are discussed in the paper and mainly focussed on FE models with a large number of degrees of freedom. Hence an update method has been introduced, which leads to an improved model in a relatively small quantity of computer time. It can be shown, that based on measured eigenfrequencies and calculated eigenvectors, an updating of FE-models for real engineering problems, by changing the mass matrix only, is a very efficient procedure with a surprisingly good quality updated model.

Response mechanisms of reinforced concrete panels to the combined effect of close-in blast and fragments

2020 ◽  
pp. 204141962092312
Author(s):  
Paolo Del Linz ◽  
Tat Ching Fung ◽  
Chi King Lee ◽  
Werner Riedel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Blast Loading ◽  
Blast Waves ◽  
Combined Loading ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Differential Model ◽  
Modelling Approach

The effect of cased explosives on reinforced concrete components is important for the design of protective structures, since the interaction between the fragments and blast waves can modify or even amplify the damage caused. This work deals with the development of finite element analysis techniques to simulate the combined loading and to understand this interaction. In this work, an experiment conducted with a cased explosive and further tests from the literature were used together to develop and stepwise validate finite element analysis models of the different loading phases. The casing fragment velocities and spatial distribution were derived from explosive expansion simulations of the hull using the smooth particle hydrodynamics method together with a momentum conserving penalty contact. The blast loading applied on the concrete plate was based on established empirical formulae, acting at the same times as the fragments. Comparing the final damage with the experimental records revealed good agreement for most damage patterns. The model was used to identify the different damage evolution stages, such as shock-induced shear plug formation and subsequent structural dynamic bending with the associated damage. In addition, differential model variants with fragment and blast loading in isolation were simulated to resolve the response and damage of each loading component. The blast load caused predominantly bending deformations and damage, while the fragments caused similar cratering as seen in the combined case. However, the final combined damage was larger than that caused by each phenomenon. In the given situation, the fragments created most damage, but the established modelling approach opens the perspective to study these effects also for other ratios of explosive to casing weight and scaled distances, where the contributions might differ. Establishing a valid modelling approach is thus an important step towards more insight into the interaction of these complex loading types and damage effects.

scholarly journals Feasibility simulation of aseismic structure design for long-span bridges

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 1107-1117
Author(s):  
Li Lai
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Seismic Isolation ◽  
Structure Design ◽  
Bridge Structure ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Dynamic Reliability ◽  
Long Span Bridges ◽  
Long Span

Abstract In the traditional finite element analysis method, when simulating the feasibility of aseismic structure design of long-span bridges, only finite element analysis is carried out on the bridge structure without considering the aseismic situation of the aseismic structure of the bridge under different schemes, which leads to one-sidedness of the simulation results. Therefore, a new simulation method for the feasibility study of seismic design of long-span bridges is proposed in this paper. 5 seismic isolation schemes for long-span bridge structures are designed. The lock-up devices and liquid viscous dampers are deployed in bridge structure. Numerical simulation of bridge structure is carried out by establishing calculation model and improved hierarchical Kerr spring model. The responses of long-span bridges under seismic loading for 5 seismic isolation schemes are analyzed. On this basis, the seismic performance of long-span bridges is tested by using the multi-point excitation motion equation, the response power spectrum and the structural dynamic reliability analysis based on the first transcendental failure criterion. Experimental results show that all the five seismic isolation schemes are feasible, and the seismic effect of the schemes 4 and 5 is the strongest. The maximum horizontal thrust of pier top is 6.27E+062, 0.50E+07 and 6.00E+06, 2.78E+07, respectively. The proposed method can be used to simulate the seismic response of long-span bridges.

Study of Passive Vibration Absorbers Attached on Beam Structure

2014 ◽  
Vol 660 ◽  
pp. 511-515 ◽  
Author(s):  
Izzuddin Zaman ◽  
Muhammad Mohamed Salleh ◽  
Maznan Ismon ◽  
Bukhari Manshoor ◽  
Amir Khalid ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequency ◽  
Structural Vibration ◽  
Mode Shapes ◽  
Small Scale ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Element Analysis ◽  
Structural Dynamic

Structural vibration is undesirable, wasting energy and possibly leading to excessive deflections and structure and machine’s failure. In order to reduce structural vibration, one of the common way is considering vibration absorber system attach to the structure. In this study, a vibration absorber is developed in a small scale size. The host structure selected for the study is a fixed-fixed ends beam. The effectiveness of vibration absorbers attached to a beam is investigated through experimental study. In prior to experiment, a finite element analysis of Solidworks® and analytical equations of Matlab® are produced in order to determine the structural dynamic response of the beam, such as the natural frequency and mode shapes. The preliminary results of finite element analysis demonstrate that the first five natural frequency of fixed-fixed end beam are 17Hz, 46Hz, 90Hz, 149Hz and 224Hz, and these results are in agreement with the beam’s analytical equations. However, there are slight discrepancies in experiment result due to noise and error occurred during the setup. In the later stage, the experimental works of beam are performed with attached vibration absorber. Result shows that the attachment of vibration absorber produces better outcome, which is about 45% vibration reduction. It is expected that by adding more vibration absorber to the structure, the vibration attenuation can significant.

The Application of Multiple Vibration Neutralizers for Vibration Control in Aircraft

2014 ◽  
Vol 629 ◽  
pp. 191-196 ◽  
Author(s):  
Izzuddin Zaman ◽  
Muhammad Mohamed Salleh ◽  
Bukhari Manshoor ◽  
Amir Khalid ◽  
Sherif Araby
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Vibration Control ◽  
Natural Frequency ◽  
Thin Plate ◽  
Mode Shapes ◽  
Modern Trend ◽  
Small Scale ◽  
Element Analysis ◽  
Structural Dynamic

A current challenge for researchers is the design and implementation of an effective vibration control method that reduces vibration transmission from vehicle structures such as aircraft. This challenge has arisen due to the modern trend of utilizing lightweight thin panels in aircraft structural design, which have the potential to contribute towards significant vibration in the structures. In order to reduce structural vibration, one of the common approaches is considering vibration neutralizer system attached to the structure. In this study, a vibration neutralizer is developed in a small scale size. The effectiveness of attached vibration neutralizers on a thin plate are investigated through experimental study. Prior to the experiment, a finite element analysis of Solidworks® and analytical modelling of Matlab® are produced in order to determine the structural dynamic response of the thin plate such as the natural frequency and mode shapes. The preliminary results of finite element analysis demonstrate that the first four natural frequency of clamped plate are 48Hz, 121Hz, 194Hz and 242Hz, and these results are in agreement with the plate’s analytical equations. However, there are slight discrepancies in the experiment result due to noise and error occurred during the set up. In the later stage, the experimental works of thin plate are performed with attached vibration neutralizer. Result shows that the attachment of vibration neutralizer produces better outcome, which is about 41% vibration reduction. It is expected that by adding more vibration neutralizer to the structure, the vibration attenuation of thin plate can be significant.

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