scholarly journals Residual life estimation of structural beam using experimental and numerical modal analysis methods

2020 ◽  
Vol 4 (2) ◽  
pp. 135-146
Author(s):  
Ganda Anand Siva ◽  
Shinigam Ramakrishna
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Residual Life ◽  
Crack Depth ◽  
Common Element ◽  
Cracked Beam ◽  
Element Analysis ◽  
Crack Location ◽  
Parametric Studies ◽  
Ship Propeller

A structural beam is a common element in many mechanical structures such as ship propeller shaft, crane boom, and air craft wings. In the present paper experimental and numerical modal analysis are carried out for estimating the damage detection, geometric location of the damage, severity of damage and residual life of structural beam to prevent unexpected failures of the mechanical structures. Experimental and numerical modal analysis results for healthy and cracked beam are compared for validation of numerical methodology used in the present paper. Experimental modal analysis is performed on both healthy and cracked beam with the help of impact hammer, acceleration sensor and FFT analyzer associated with EDM (Engineering Data Management) software. Modal tests are conducted using impact method on selected locations of the entire healthy and cracked beam to find the first three natural frequencies, which are used to detect the presence of damage and geometric location of the damage. Three parametric studies are carried out to know the effect of crack depth, crack location and crack orientation on the natural frequencies of the cracked beam. Finally,  residual life of a healthy and cracked beam was estimated using Basiquin’s equation and finite element analysis software called ANSYS 18.1.

Vibration Analysis of a Cracked Beam on an Elastic Foundation

2016 ◽  
Vol 16 (05) ◽  
pp. 1550006 ◽  
Author(s):  
Ali Çağri Batihan ◽  
Fevzi Suat Kadioğlu
Keyword(s):  
Elastic Foundation ◽  
Cross Sections ◽  
Natural Frequencies ◽  
Crack Depth ◽  
Cracked Beam ◽  
Crack Location ◽  
Transverse Vibrations ◽  
Foundation Type ◽  
Foundation Parameters ◽  
Open Edge

The transverse vibrations of cracked beams with rectangular cross sections resting on Pasternak and generalized elastic foundations are considered. Both the Euler–Bernoulli (EB) and Timoshenko beam (TB) theories are used. The open edge crack is represented as a rotational spring whose compliance is obtained by the fracture mechanics. By applying the compatibility conditions between the beam segments at the crack location and the boundary conditions, the characteristic equations are derived, from which the nondimensional natural frequencies are solved as the roots. Sample numerical results showing the effects of crack depth, crack location, foundation type and foundation parameters on the natural frequencies of the beam are presented. It is observed that the existence of crack reduces the natural frequencies, whereas the elasticity of the foundation increases the stiffness of the system and thus the natural frequencies. It is also observed that the type of elastic foundation has a significant effect on the natural frequencies of the cracked beam.

scholarly journals Vibration Modes and Parameter Analysis of V-Shaped Electrothermal Microactuators

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Zhuo Zhang ◽  
Yueqing Yu ◽  
Xuping Zhang
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Frequency Equation ◽  
Parameter Analysis ◽  
Mode Shapes ◽  
Element Analysis ◽  
Shaped Beam ◽  
The Finite Element Analysis ◽  
Parametric Studies ◽  
First Time

Comprehensive analysis on the modal characteristics of V-shaped electrothermal microactuators is presented in this paper for the first time. Considering the unique geometric characteristics of the V-shaped beam, that is, two inclined beams supporting a movable shuttle, both the lateral and longitudinal deflections are taken into account in the modal analysis. Boundary and continuity conditions are employed to obtain the frequency equation. Natural frequencies are then obtained by solving the frequency equation. Mode shapes corresponding to their natural frequencies are also calculated analytically. The theoretical modal analysis is verified with the finite element analysis using ANSYS software. Based on the model analysis, this paper further investigates the relationship between natural frequencies and the volume scaling of the V-shaped beam. Finally, comprehensive parametric studies in terms of material properties and structural dimensions are conducted to provide insights and guidance in designing the V-shaped beam electrothermal microactuators.

Identification of Transverse Crack in Beam like Structure Using PSO

2014 ◽  
Vol 548-549 ◽  
pp. 1728-1734
Author(s):  
D.N. Thatoi ◽  
S. Choudhury ◽  
P.K. Jena ◽  
H.C. Das ◽  
A.K. Subudhi
Keyword(s):  
Natural Frequencies ◽  
Crack Depth ◽  
Population Based ◽  
Beam Structure ◽  
Cracked Beam ◽  
Swarm Optimization ◽  
Crack Location ◽  
Flexibility Matrix ◽  
Local Flexibility ◽  
Open Edge

The current proposed method has been developed using particle swarm optimization (PSO) technique. A single transverse open edge crack on a beam structure has been modeled using local flexibility matrix to determine natural frequencies. The PSO is a population based; bio-inspired evolutionary optimization algorithm that has been implemented for detection of crack. The frequencies obtained from analytical method have been used to train the PSO to get the desired output such as; relative crack depth and relative crack location. Mathematical modeling of the cracked beam structure is being done to ensure the integrity of the above algorithms. The results from the PSO show that both the size and location of the crack can be predicted efficiently through the proposed PSO.

Approximate analytical analysis of longitudinal natural frequencies of a cracked beam

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hillal Ayas ◽  
Lyes Amara ◽  
Mohamed Chabaat
Keyword(s):  
Natural Frequencies ◽  
Crack Depth ◽  
Experimental Tests ◽  
Frequency Equation ◽  
Cracked Beam ◽  
Lagrange Inversion ◽  
Approximate Analytical Expression ◽  
Content Type ◽  
Inversion Theorem ◽  
Crack Location

PurposeIn this paper, an approximate analytical approach is developed for the determination of natural longitudinal frequencies of a cantilever-cracked beam based on the Lagrange inversion theorem.Design/methodology/approachThe crack is modeled by an equivalent axial spring with stiffness according to Castigliano's theorem. Thus, an implicit frequency equation corresponding to cantilever-cracked bar is obtained. The resulting equation is solved using the Lagrange inversion theorem.Findingseffect of different crack depths and crack positions on natural frequencies of the cracked beam is analyzed. It is shown that an increase in the crack depth ratio produces a decrease in the fundamental longitudinal natural frequency of a cracked bar. Furthermore, approximate analytical results are compared with those obtained numerically as well as from experimental tests.Originality/valueA new approximate analytical expression of a fundamental longitudinal frequency, as a function of crack depth and crack location, is obtained.

Parametric Evaluation on the Response of Damaged Simple Supported Structure Under Transit Mass

2017 ◽  
Author(s):  
Shakti P. Jena ◽  
Dayal R. Parhi ◽  
B. Subbaratnam
Keyword(s):  
Finite Element Analysis ◽  
Integral Method ◽  
Critical Speed ◽  
Crack Depth ◽  
Element Analysis ◽  
Simply Supported ◽  
Crack Location ◽  
Integral Converge ◽  
Duhamel Integral ◽  
Ansys Workbench

In the present article, the responses of a double cracked simply supported beam have been investigated. The responses of the structure are determined using Duhamel integral method numerically and validated with finite element analysis (FEA) using ANSYS WORKBENCH 2015 along with experimental verifications. The mass is moving on the structure in terms of critical speed of the structure. The normalized deflections of the structure at different damaged configurations are calculated. The influences of speed, mass, crack depth and crack location on the structures response are investigated. It is observed that the results obtained from Duhamel integral converge well with FEA and experimental verifications.

Crack Growth in Twisted Rubber Disks. Part 3. Effects of Crack Depth and Location

2003 ◽  
Vol 76 (5) ◽  
pp. 1276-1289 ◽  
Author(s):  
A. N. Gent ◽  
O. H. Yeoh
Keyword(s):  
Fracture Energy ◽  
Crack Depth ◽  
Element Analysis ◽  
Crack Location ◽  
Crack Behavior ◽  
Disk Size ◽  
Shallow Crack ◽  
Deep Crack ◽  
Disk Height ◽  
Long Cylinder

Abstract A simple analysis of the fracture energy for a shallow ring crack in a twisted rubber disk is presented and compared to a linear fracture mechanics solution for a similar crack in an infinitely long cylinder. The analysis predicts that the fracture energy increases linearly with crack depth. Since a previous analysis shows that the fracture energy subsequently decreases with crack depth when the crack is deep, it follows that the fracture energy passes through a peak as it transitions from shallow crack to deep crack behavior. The transition occurs when the crack depth becomes comparable to a fraction of the disk height. The analysis is supported by the results of finite element analysis. In addition, the effects of disk size, crack location (in the middle of the cylinder vs. at the bonded ends) and material properties are also considered.

scholarly journals Influence of Crack on Modal Parameters of Cantilever Beam Using Experimental Modal Analysis

2018 ◽  
Vol 1 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Siva Sankara Babu Chinka ◽  
Balakrishna Adavi ◽  
Srinivasa Rao Putti
Keyword(s):  
Numerical Analysis ◽  
Modal Analysis ◽  
Natural Frequency ◽  
Cantilever Beam ◽  
Damping Ratio ◽  
Crack Depth ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Crack Location

In this paper, the dynamic behavior of a cantilever beam without and with crack is observed. An elastic Aluminum cantilever beams having surface crack at various crack positions are considered to analyze dynamically. Crack depth, crack length and crack location are the foremost parameters for describing the health condition of beam in terms of modal parameters such as natural frequency, mode shape and damping ratio. It is crucial to study the influence of crack depth and crack location on modal parameters of the beam for the decent performance and its safety. Crack or damage of structure causes a reduction in stiffness, an intrinsic reduction in resonant frequencies, variation of damping ratios and mode shapes. The broad examination of cantilever beam without crack and with crack has been done using Numerical analysis (Ansys18.0) and experimental modal analysis. To observe the exact higher modes of beam, discretize the beam into small elements. An experimental set up was established for cantilever beam having crack and it was excited by an impact hammer and finally the response was obtained using PCB accelerometer with the help sound and vibration toolkit of NI Lab-view. After obtaining the Frequency response functions (FRFs), the natural frequencies of beam are estimated using peak search method. The effectiveness of experimental modal analysis in terms of natural frequency is validated with numerical analysis results. This paper contains the study of free vibration analysis under the influence of crack at different points along the length of the beam.

Vibration Analysis Method of Cracked Beam Based on the Principle of Energy

2011 ◽  
Vol 94-96 ◽  
pp. 1633-1637
Author(s):  
De Liang Chen ◽  
Wen Ting Wang ◽  
Feng Liu
Keyword(s):  
Vibration Analysis ◽  
Natural Frequencies ◽  
Analysis Method ◽  
Structural Damping ◽  
Linear Vibration ◽  
Cracked Beam ◽  
Energy Principle ◽  
Crack Location ◽  
Nonlinear Elastic ◽  
Elastic Mechanics

Using the theory of nonlinear elastic mechanics and fracture mechanics, the equation of motion governing equation of cracked beam is derived by the energy method, and solved with separation method of variables. Vibration analysis method based on the energy principle in this paper is proved feasible.Through numerical analysis, the effects of structural damping, crack location and depth on natural frequencies of linear vibration is investigated.

Finite Element Modal Analysis for Steam Turbine Blade Based on ANSYS

2012 ◽  
Vol 260-261 ◽  
pp. 368-371
Author(s):  
Lu Wang ◽  
Shun Qiang Ye ◽  
Rui Meng
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Natural Frequencies ◽  
Crack Location ◽  
Finite Element Software ◽  
Vibration Fatigue ◽  
Steam Turbine Blade ◽  
Twisting Deformation

In response to the vibration fatigue fracture of the steam turbine blade,we construct the 3D model of cracked blade based on the actual crack location,then modal analysis is conducted to the blade with crack and one without crack using the finite element software ANSYS.Thus,we can get the respective natural frequencies and the figure of main vibration modes.The comprasion results show that the existence of the crack can make the natural frequencies of blades drop and the blades have the greatest sway and twisting deformation along the Y axis.These characteristics above can effectively identify the presence of blade cracked. It has crucial meaning for achieving cracked blade online monitoring.

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