An Experimental-Numerical Method for Nonlinear Structural Mechanics

1993 ◽  
Vol 60 (4) ◽  
pp. 875-882
Author(s):  
F. J. M. Starmans ◽  
W. A. M. Brekelmans ◽  
J. D. Janssen
Keyword(s):  
Structural Data ◽  
Measured Data ◽  
Geometrically Nonlinear ◽  
The Finite Element Method ◽  
Likelihood Estimator ◽  
Rigid Plastic ◽  
Material Points ◽  
Nonlinear Rigid ◽  
Plastic Case ◽  
Nonlinear Structural Mechanics

A maximum likelihood estimator and the finite element method are used to construct a tool for estimating the state of continuous structures from measured structural data. These structural data can, for example, consist of displacements of material points and stresses or strains at material points. The statistical uncertainty of the measured data is supposed to be known. An approximation for the uncertainty of the estimated state can be given. The analyzing tool, elaborated for the geometrically nonlinear rigid plastic case, is useful for evaluation of feasibility and accuracy of experimental set-ups. An example of application of the tool is presented.

Development of Stacked-Type Electrostatic Actuator Using Two Ribbon Films

2013 ◽  
Vol 25 (2) ◽  
pp. 324-332 ◽  
Author(s):  
Kazuo Okuda ◽  
◽  
Keiji Saneyoshi ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reduction Rate ◽  
Measured Data ◽  
The Other ◽  
Artificial Muscles ◽  
Electrostatic Actuator ◽  
The Finite Element Method ◽  
Nonlinear Structural Analysis ◽  
Working Region

A new stacked-type electrostatic actuator with two ribbon films has been developed to be applied to artificial muscles. In this paper, spring characteristics of the actuator have been simulated and compared to measured data. There are two regions in spring characteristics of the actuator: one is the working region where the actuator contracts easily, and the other is the overload region where the actuator is extended only negligibly by the load. Spring characteristics of the actuator have been simulated by nonlinear structural analysis including the contact problem using the finite element method. It is understood that spring characteristics of working and overload regions can be improved by thinning the hinge and by thickening the electrode. The stroke of the actuator can be controlled, furthermore, by changing the length of the hinge. When the size of the actuator is reduced and actuators are integrated until they become the same volume, voltage applied to the actuator to generate the same force is reduced in proportion to the reduction rate while the actuator keeps the same spring characteristics and stroke.

Elasto-Plastic Indentation of a Layered Medium

1974 ◽  
Vol 96 (2) ◽  
pp. 97-103 ◽  
Author(s):  
F. E. Kennedy ◽  
F. F. Ling
Keyword(s):  
Plastic Deformation ◽  
Layered Medium ◽  
Considerable Effect ◽  
Plastic Layer ◽  
The Finite Element Method ◽  
Rigid Substrate ◽  
Indentation Size ◽  
Indentation Tests ◽  
Plastic Indentation ◽  
Plastic Case

An analysis is performed, using the finite element method, of the indentation of a thin elasto-plastic layer resting on or attached to a substrate of a different material, which may also deform plastically. The indentation size, contact pressure, applied load, and amount of plastic deformation are found for the elasto-plastic case, and the results are compared with those found by an elastic analysis. It is found that plastic deformation, which occurs in all indentation tests, has a considerable effect on the results, and that the deformation in the indented layer is also affected by such variables as: the material properties of both layer and substrate, the thickness of the layer, and the condition of the interface between layer and substrate. The “piling-up” that has been observed experimentally in indentation tests is found to depend on the same variables and occurs especially when a thin layer is adhered to a more rigid substrate. The analysis is valid throughout the loading-unloading cycle.

Effect Review of the Strengthening Technique by Use of the External Prestressing

2011 ◽  
Vol 121-126 ◽  
pp. 3258-3262
Author(s):  
Long Sheng Bao ◽  
Dan Yang ◽  
Ling Yu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Section ◽  
Prestressed Concrete ◽  
Measured Data ◽  
The Finite Element Method ◽  
Construction Monitoring ◽  
External Prestressing ◽  
Monitoring Result ◽  
Strengthening Technique

The grand bridge of Fu Feng is prestressed concrete cross-section continuous girder, which is reinforced with external prestressing. Construction monitoring is based on the measured data, and using the finite element method to calculate, it need to analyze the control of the stress and deflection in the construction to ensure to make the construction could be completed on schedule and to reach an ideal type. The field monitoring result indicates that the type of bridge did improve and reach the requirement of design after reinforcement.

scholarly journals SHM System and a FEM Model-Based Force Analysis Assessment in Stay Cables

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1927
Author(s):  
Jan Biliszczuk ◽  
Paweł Hawryszków ◽  
Marco Teichgraeber
Keyword(s):  
Measured Data ◽  
The Finite Element Method ◽  
Force Analysis ◽  
Fem Model ◽  
Temperature Changes ◽  
The Third ◽  
Cable Stayed Bridge ◽  
Stay Cables ◽  
Durability Assessment ◽  
Cable Stays

The Rędziński Bridge in Wrocław is the biggest Polish concrete cable-stayed bridge. It is equipped with a large structural health monitoring (SHM) system which has been collecting the measured data since the bridge opening in the year 2011. This paper presents a comparison between the measured data and the finite element method (FEM) calculations, while taking into account 7 years of data collection and analyses. The first part of this paper concerns the SHM application. In the next part, which contains comparisons between forces in cables and temperature changes throughout the structure, the measured data are presented. The third part includes SHM-based calculations and simulations with a complex FEM model to check the measured data and to estimate future measurements. The last part contains a durability assessment calculation for the cable stays.

Localization and Quantification of Breathing Crack

2005 ◽  
Vol 128 (2) ◽  
pp. 458-462 ◽  
Author(s):  
Milos Musil
Keyword(s):  
Approximate Analytical Solution ◽  
Second Harmonic ◽  
Bilinear System ◽  
Measured Data ◽  
Harmonic Load ◽  
The Finite Element Method ◽  
Breathing Crack ◽  
Series Representations ◽  
Nonlinear Analytical Model ◽  
The Mathematical Model

The possibility of localizing and quantifying a crack in a vibrating structure based on measured vibration amplitudes of the first and second harmonic in some locations of the structure and utilizing the mathematical model of an undamaged system, will be the focus of this paper. The structure is modeled by means of the finite element method. The effect of the breathing crack is modeled by the nonlinear (bilinear) stiffness of the element with the crack. The excitation of the system is characterized by the simultaneous effect of static and dynamic harmonic load. The Fourier series representations of the approximate analytical solution of a weakly bilinear system was used to obtain the localization and quanification a weak bilinearity. The method was documented on an elementary example, in which simulated measured data were determined by the use of the numerical solution of the nonlinear analytical model of a structure with a crack.

The Finite Element Simulation of Thermal Deformation and Microstructure Evolution Forecast of AZ61 Alloy

2014 ◽  
Vol 989-994 ◽  
pp. 548-551
Author(s):  
Quan Li ◽  
Wen Jun Liu ◽  
Ren Ju Cheng ◽  
Cheng Li ◽  
Shan Jiang ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Simulation Software ◽  
The Finite Element Method ◽  
Rigid Plastic ◽  
Production Forecast ◽  
Optimization Of Process Parameters ◽  
Element Simulation ◽  
Calculation Results

In this paper, rigid-plastic finite element simulation software Marc / Auto-forge reflect compression AZ61B magnesium alloy case. Simulation results show that the stress, strain and temperature distribution within the sample is uneven, uneven distribution affect the organization, and with the changes in the deformation process and calculation results with the experimental data exactly. The finite element method can be used in the actual production forecast after tissue deformation components, optimization of process parameters to control the quality of the finished piece.

The Research on Environment Vibration due to Subway with Rail Pads of Frequency-Dependent Stiffness

2014 ◽  
Vol 580-583 ◽  
pp. 1153-1160
Author(s):  
Fan Yang ◽  
Kai Wei ◽  
Yan Chen Song
Keyword(s):  
Frequency Domain ◽  
Ground Vibration ◽  
Measured Data ◽  
Frequency Domain Method ◽  
The Finite Element Method ◽  
Frequency Range ◽  
Ground Acceleration ◽  
Frequency Dependent ◽  
Analysis Technique ◽  
Coupling Dynamics

Based on Vehicle-Track Coupling Dynamics and the spectrum analysis technique of the Finite Element Method, a frequency-domain method of environment vibration due to subway is put forward and frequency-range distribution of ground acceleration is discussed. Compared with the measured data, the result shows that after considering frequency-dependent stiffness of rail pad, the error is less than 0.3dB in the frequency range of 0-30 Hz, but it is up to 11.8 dB in the frequency range of 50-100 Hz. And the frequency-domain distribution of ground vibration changes too. Thus, the frequency-dependent stiffness of rail pads is not negligible in the prediction of environment vibration generated by subway.

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