Residual Force Method Research Articles

Damage Detection in Members and Connections of Plane Frame with Flexible Connections Using Residual Force Method and Whale Optimization Algorithm

Damage Detection in Members and Connections of Plane Frame with Flexible Connections Using Residual Force Method and Whale Optimization Algorithm

Elastic–plastic analysis of the plane strain under combined thermal and pressure loads with a new technique in the finite element method

Abstract This research aims to find a new way to address thermal loads within the framework of the elastic–plastic relationship, especially when the loads, such as thermal and pressure ones, are combined. While the residual force method was employed to attempt to find the convergence of a nonlinear solution, it was unable to do so. For this purpose, a mathematical relationship was derived to address thermal loads and add them to the hierarchy of the specified elements method as a subroutine. The findings of the developed program were verified by comparing the numerical results with those of the analytical solution of a thick-walled cylinder loaded with heat load and internal pressure; the results proved the correctness and accuracy of the method used. The method offers a way to redevelop old programs that are unable to effectively address the thermal load in elastic–plastic relations without changing said programs significantly but only by adding the subroutine and some very simple modifications. The solution technique provided in this article can be utilized in many related cases, such as plane stress, axisymmetric solid, and three-dimensional stress analyses.

Residual Force Method for damage identification in a laminated composite plate with different boundary conditions

The strongest point about damage identification based on the dynamic measurements, is the ability perform structural health evaluation globally. Researchers in the last few years payed more attention to damage indicators based on modal analysis using either frequencies, mode shapes, or Frequency Response Functions (FRFs). This paper presents a new application of damage identification in a cross-ply (0°/90°/0°) laminated composite plate based on Force Residual Method (FRM) damage indicator. Considering single and multiple damages with different damage levels. As well as investigating the SSSS and CCCC boundary conditions effect on the estimation accuracy. Moreover, a white Gaussian noise is introduced to test the challenge the technique. The results show that the suggested FRM indicator provides accurate results under different boundary conditions. Favouring the SSSS boundary condition than the CCCC for 3% noise.

Determination of Crack Pattern in Concrete Structures Using Applied Element Method

Applied Element Method (AEM) is a relatively new method for structural analysis developed by Kimiro Meguro and Hatem Tagel Din in 1997. It can capture the behavior of structure up to failure. In this method, structure is discretized into rigid elements connected by springs. The stiffness matrix of the structure consists of that of springs only. Here, the method is used to find out the failure load and predict the crack propagation. Two methods are available to determine the crack pattern namely unloading-reloading method and residual force method. These approaches are used to maintain equilibrium during the process of cracking. In this paper, these methods are discussed and they are used for the analysis of plain concrete beams with different support conditions.

Rheological-dynamical analogy for analysis of vibrations and low cycle fatigue in internally damped inelastic frame structures

This is a study of viscoelastoplastic (VEP) vibrations and their use for the analysis of low cycle fatigue in internally damped inelastic frame structures (IDIFSs). The background of this inelastic theory is presented in the framework of a mathematical-physical analogy between the rheological model and a dynamical model with viscous damping. The rheological-dynamical analogy (RDA) is a type of inelastic analysis, which transforms one category of material non-linear problems to simpler linear dynamical problems using modal analysis. The aim of this paper is to define internal damping based on both the dynamic modulus and modal damping ratios. The idea underlying these approaches is that fatigue damage appears if internal damping is unevenly distributed over the elements of a structure. The residual force method, which requires the use of the finite element method (FEM), is used for the location of damage and derivation of the fatigue damage vector. Finally, the effective force vector is derived from damage mechanics. An analysis of damaged IDIFSs made of reinforced concrete is carried out. It is shown that the RDA, which correlates with the main mechanical properties of the material measured, can improve the prediction of fatigue damage caused by low cycle fatigue.

Damage localization and quantification of composite beam structures using residual force and optimization

Structural Health Monitoring (SHM) and impact monitoring of composite structures have become important research topics in the recent year. In this research, a non-destructive vibration-based damage detection method is formulated using Genetic Algorithm (GA) and compared with classical method. The robustness and reliability of the capability to locate and to estimate the severity of damage, based on changes in dynamic characteristics of a structure, is investigated. The objective function for the damage identification problem is established by using the residual force method (FRM). Numerical experiments using finite element analysis are performed on composite beams with different damage scenarios in order to clarify the validity of the developed technique. The comparison between estimated and real damage illustrates the efficiency of the algorithm in damage detection. The results show that the present approach is correct and efficient for detecting structural local damages in composite beam structures.

Damage localization and quantification of composite stratified beam Structures using residual force method

In this paper, the problem of using measured modal parameters to detect and locate damage in beam composite stratified structures with four layers of graphite/epoxy [0°/902°/0°] is investigated. A technique based on the residual force method is applied to composite stratified structure with different boundary conditions, the results of damage detection for several damage cases demonstrate that using residual force method as damage index, the damage location can be identified correctly and the damage extents can be estimated as well.

DAMAGE DETECTION OF SPACE STRUCTURES USING CHARGED SYSTEM SEARCH ALGORITHM AND RESIDUAL FORCE METHOD

Changes in dynamic properties of structures indicate occurrence of damages in the structures. In this paper, a new two stage algorithm for damage detection of large structure is introduced. A modified Residual Force Method is utilized to locate the damage regions in structures, especially barrel vaults, and then the enhanced Charged System Search (CSS) Algorithm is used to quantify the amount of damage. The proposed method requires modeling the structure in its undamaged state to obtain the dynamic properties such as frequencies and mode shapes of the structure in its damaged state. The validation of the method is investigated by some numerical study on space structures. It is shown that if dynamic properties are not affected by noise, the method can still identify damaged elements, but when measurements are corrupted by noise, the exact determination of damaged region is not possible. To overcome this problem, it is proposed to repeat measuring modal properties several times, and then with utilizing residual force vector and statistical analysis, the damaged region is predicted accurately. In this paper, a modified vector is utilized for enhancing efficiency of the modal Residual Force method and suppressing effect of noise, and then a threshold is defined to distinguish DOFs associated with damaged elements. Then, using the CSS algorithm, severities of damaged elements are assessed.

Damage detection of plate-like structures based on residual force vector

Structural health monitoring is essential to maintain the structural integrity by predicting problems in an early time. This consequently could be reflected on extending the life time of structures. Nondestructive tests based on dynamic measures are usually fast and economic in detecting damages of structures. Various numerical techniques together with recording time histories are used for this purpose. This paper presents a numerical method for damage detection in plate-like structures. The modeling of damage was conducted commercially using the module of MatLab. Comparison of different mode shapes was used in the analysis to detect the location of local damage based on residual force vector. The technique utilized the node residual force vector to locate and evaluate the degree of the suspected damaged elements. In the current study, three configurations for plates were used. The study also concentrated on the efficiency of the new method in identifying damages of different degradation levels. The plates were subjected to different combinations of artificial damages applied at various positions on each plate. The study was not only able to identify the location but also the degree of damage in plates. It has been noted that identification of severe degradation was more precisely identified. As a result, the residual force method is the simplest damage quantification technique which approved to be accurate enough to be used in practical applications.

Error Location in Structural Dynamic Model of a Rocket Structure

Structural dynamic characteristics of the aerospace structures are essential to obtain the structural responses due to dynamic loads during its mission. The structural dynamic parameters of the aerospace structures are frequencies, associated mode shape and damping. Usually finite element (FE) model of the aerospace structures are generated to estimate the frequencies and the associated mode shape. These FE models are validated by modal survey/ground resonance tests to ensure its completeness and correctness. The modeling deficiencies, if any, in these FE models have to be corrected. This paper describes the method to locate the FE modeling errors using residual force method.

Vibration based damage detection in a uniform strength beam using genetic algorithm

Cantilever steel beams of uniform strength are having various industrial applications. In particular when it is used as leaf spring it undergoes very large deflection in comparison to beam of uniform cross section. The damage occurs in these beams mainly due to fatigue loading. Early detection of damage in such type of beams is very essential to avoid a major failure or accident. In this paper, firstly formulation of an objective function for the genetic search optimization procedure along with the residual force method are presented for the identification of macroscopic structural damage in an uniform strength beam. Two cases have been investigated here. In the first case the width is varied keeping the strength of beam uniform throughout and in the second case both width and depth are varied to represent a special case of uniform strength beam. The developed model require experimentally determined data as input and detect the location and extent of the damage in the beam. Here, experimental data are simulated numerically by using finite element models of structures with inclusion of random noise on the vibration characteristics. It has been shown that the damage may be identified for the said problems with a good accuracy.

Structural damage identification using system dynamic properties

A damage detection method is presented for the identification and quantification of damage that leads to a change in the structure’s mass and/or stiffness properties. The proposed method requires the use of finite element to model the structure in its undamaged state as well as information on the dynamic properties such as frequencies and mode shapes of the structure in its damaged state. The technique is applicable to any structure that can be accurately modeled using the finite element method and whose frequencies and mode shapes can be reliably measured. A structure pseudo force vector derived from the residual force method is described to locate the damaged regions in the structure. A matrix condensation approach in conjunction with a proportional damage model is then employed to quantify the damage by calculating the change in stiffness and mass properties of the damaged elements in the structure. The validity of the method is demonstrated by applying it to three structures: a beam, a frame and a plate. It is shown that if the amount of damage is not excessively large, the proposed method can be used to detect damage in these structures even when the measured system dynamic properties are slightly erroneous.

Structural Damage Detection by Genetic Algorithms

A two-stage procedure utilizing incomplete measurements to assess the location and extent of structural damage is presented. In the first stage, candidate damaged elements are identified using the residual force method. Based on a priori knowledge from the first stage, the damage extent is determined from candidate elements using a proposed optimization scheme based on the method of simulated evolution.

AN APPLICATION OF GENETIC ALGORITHMS TO IDENTIFY DAMAGE IN ELASTIC STRUCTURES

A technique currently under development for the detection of macroscopic structural damage in elastic structures is described. The location and quantification of the extent of the damage in elastic structures is described. The location and quantification of the extent of the damage is performed with genetic algorithms implemented by using the residual force method which is based on conventional modal analysis theory. A brief survey of the literature published on the subject, the theory of genetic algorithms and the residual forces method are included and a new formulation of an objective function for the genetic search optimization procedure is presented. The results of test cases are included in order to illustrate the techniques presented. In these examples, experimental data were simulated numerically by using finite element models of structural systems and, as demonstrated, it has been possible to identify the damage introduced to a reasonable level of accuracy.

Comparison of two viscoplastic flow laws as applied to a problem of crack growth

The finite element method is incorporated in the study of the mechanical response of an advanced nickel-based superalloy IN-100 with inelastic time-dependent material behavior at 1350°F (732°C). The material's time-dependent plastic deformation (viscoplasticity) is analytically modeled by both the Bodner-Partom equations and the Malvern overstress flow law. The Bodner-Partom constitutive equations involve the use of nine material parameters which are determined from a complex procedure. Various forms of the Malvern overstress flow law are studied since this flow law uses only a few material parameters which are easily determined from uniaxial experimental data. Both the Malvern and Bodner-Partom constitutive equations are formulated in multiaxial from in a two-dimensional finite element program incorporating the constant strain triangle. The program is applied to the analysis of a center crack plate of IN-100 under a monotonic tension load. The residual force method is utilized to handle variations in material stiffness due to time-dependent plastic deformation. A Hybrid Experimental Numerical (HEN) procedure is used in order to track crack opening displacement near the crack tip. This HEN procedure controls the crack growth rate in the finite element model by following the experimental displacement rates accurately. Thus, crack growth predictions become a byproduct of both the rate sensitive model and the near field experimental displacement rates. The predictions of the two constitutive models are compared with respect to total plastic work and effective stress profiles in addition to crack growth rate.

Note on the modified Aitken accelerator for use in the residual force method

AbstractSome considerations regarding the application of the modified Aitken accelerator to solution of problems of elasto‐plasticity by the residual force method are discussed. An efficient technique for continuing iterations after an acceleration is given.

Note on the residual force method—Comment on reference 1

International Journal for Numerical Methods in EngineeringVolume 6, Issue 3 p. 446-447 Short Communication Note on the residual force method—Comment on reference 1 Robert G. Vos, Robert G. Vos The Boeing Company, Structures and Propulsion Organization, Huntsville, Alabama, U.S.A. Engineer.Search for more papers by this author Robert G. Vos, Robert G. Vos The Boeing Company, Structures and Propulsion Organization, Huntsville, Alabama, U.S.A. Engineer.Search for more papers by this author First published: 1973 https://doi.org/10.1002/nme.1620060315Citations: 2 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume6, Issue31973Pages 446-447 RelatedInformation