Evaluation and Repair of Cracks on Statically Loaded Beams Using Piezoelectric Actuation

2021 ◽  
Vol 11 (1) ◽  
pp. 34-49
Author(s):  
Goutam Roy ◽  
Brajesh Kumar Panigrahi ◽  
Goutam Pohit
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ritz Method ◽  
Actuation Voltage ◽  
Piezoelectric Actuation ◽  
Cracked Beam ◽  
Element Analysis ◽  
Various Boundary Conditions ◽  
Piezoelectric Patch ◽  
Loading Patterns

In the present work, damage produced by a crack in a statically loaded beam is first evaluated. Subsequently, an attempt is made to repair the effect of the crack by attaching a piezoelectric patch to the beam as an actuator. Static analysis of PZT patched cracked beam along with rotational spring is performed using Ritz method. Subsequently, a finite element analysis is performed by using ABAQUS 6.12 to collate the analytical results. It is shown in the study that when PZT patch is subjected to external electric field, it yields a local reactive moment, which counters the crack effects. An equation is procured in order to compute the required actuation voltage for repairing of cracks. A parametric study is performed for various boundary conditions and loading patterns. It is distinctly noticed that the technique nullifies the discontinuity in slope curve which develops due to a crack.

New realistic hypothesis on corner stiffness of right-angle frames for increased analysis accuracy

2015 ◽  
Vol 231 (9) ◽  
pp. 1738-1748
Author(s):  
Young-Doo Kwon ◽  
Jin-Sik Han
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Equivalent Stress ◽  
Frame Structure ◽  
Element Analysis ◽  
Optimal Dimension ◽  
Various Boundary Conditions ◽  
Wide Range ◽  
Von Mises ◽  
Comparison Of The Results

Structural elements like bars, trusses, beams, frames, plates, and shells have long been used in structures and machines because of their large stiffness-to-weight ratios. The Euler–Bernoulli theory for beam elements is currently used in a wide range of engineering fields. Frames may essentially be considered to be a type of general beam with axial loads. In the analysis of a right-angle frame, the stiffness of a corner has been assumed to be infinite, which is allowable only when the frame is sufficiently slender. However, a comparison of the results of a finite element analysis showed that the assumption of rigid corner stiffness is unacceptable for most cases because of the considerable errors that result. To resolve this problem, we assumed that the stiffness of a corner in a right-angle frame was finite, which is mostly the case, and solved the problem of a right-angle frame with round corners under internal pressure. Using the derived formula based on the assumption of finite corner stiffness and the formula for the round corner stiffness, we analyzed the entire right-angle frame structure and compared the results to finite element analysis results. As a final attempt, the quasi-optimal dimension of the corner was found to exhibit the lowest von Mises equivalent stress. This proposed approach could be applied to many problems involving frames with various boundary conditions to improve the accuracy.

scholarly journals Wrinkling of Tympanic Membrane Under Unbalanced Pressure

2017 ◽  
Vol 84 (4) ◽  
Author(s):  
Bo Wang ◽  
Pravarsha Ghanta ◽  
Sandra Vinnikova ◽  
Siyuan Bao ◽  
Junfeng Liang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Solution ◽  
Tympanic Membrane ◽  
Middle Ear ◽  
Approximate Analytical Solution ◽  
Ritz Method ◽  
Transmission Function ◽  
Acoustic Transmission ◽  
Element Analysis

Mechanics of tympanic membrane (TM) is crucial for investigating the acoustic transmission through the ear. In this study, we studied the wrinkling behavior of tympanic membrane when it is exposed to mismatched air pressure between the ambient and the middle ear. The Rayleigh–Ritz method is adopted to analyze the critical wrinkling pressure and the fundamental eigenmode. An approximate analytical solution is obtained and validated by finite element analysis (FEA). The model will be useful in future investigations on how the wrinkling deformation of the TM alters the acoustic transmission function of the ear.

scholarly journals Finite Element Analysis of Graphene Oxide Based Nanoelectromechanical Capacitive Switch

2019 ◽  
Author(s):  
Rekha Chaudhary ◽  
Prasantha Reddy Mudimela
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Graphene Oxide ◽  
Dielectric Material ◽  
Actuation Voltage ◽  
Von Mises Stress ◽  
Beam Structure ◽  
Element Analysis ◽  
Capacitive Switch ◽  
Von Mises

The present work deals with finite element analysis (FEA) of a novel configuration of double clamped nanoelectromechanical (NEM) capacitive switch. Graphene oxide (GO), a graphene derivative has been used as suspended beam material in NEM switch for the first time. In the proposed work, GO is used as dielectric material having negative Poisson’s ratio value. The variation in capacitance has observed as the beam is pulled down by the actuating electrode. Analysis of pull-in voltage and von Mises stress are done using COMSOL Multiphysics, for standard and perforated GO NEM switch structures. The actuation voltage of 5.4 V for standard beam structure and 3.35 V for perforated beam structure have been achieved for the beam length of 1µm and width of 0.3 µm. The actuation voltage and von Mises stress value have reduced by making perforations in the beam. The comparative analysis of graphene and GO NEM switches have also been done in terms of von Mises stress to ensure the mechanical reliability. The von Mises stress values for GO NEM switch and graphene NEM switch are 500 MPa and 4.8 GPa respectively. This lesser value of von Mises stress in GO NEM switch makes it a good choice as beam material. The capacitive switch is demonstrated for standard and perforated beam structures. The variation in capacitance has observed as the beam is pulled down by the actuating electrode and at actuation voltage, the maximum value of capacitance obtained is 0.9403 pF.

A New Electrothermal Microactuator With Z-Shaped Beams: Design and Operation

2010 ◽  
Author(s):  
Yong Zhu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Actuation Voltage ◽  
Beam Width ◽  
Thermal Actuator ◽  
Design Parameters ◽  
Device Structure ◽  
Element Analysis ◽  
Static Test ◽  
Output Force

A new class of thermal microactuators, Z-shaped thermal actuator, is introduced in comparison with the well-established V-shaped thermal actuator. Though they share many features in common, Z-shaped thermal actuator offers several advantages: compatibility with anisotropic etching, smaller feature size, larger displacement, and larger variety of stiffness and output force. While the Z-shaped thermal actuator was modeled analytically and verified by multiphysics finite element analysis (FEA), the beam width and length of the central beam were identified as the major design parameters in tuning the device displacement, stiffness, stability and output force. Experimental measurements were taken on three arrays of Z-shaped thermal actuator with variable parameters. Results agreed well with the finite element analysis. The development of Z-shaped thermal actuator is applicable in simultaneous sensing and actuating applications. During the quasi-static test of individual Z-shaped thermal actuator, the average temperature in the device structure was estimated based on electric resistivity at each actuation voltage.

Structural Analysis of Rear Axle Casing of Tractor

2014 ◽  
Vol 592-594 ◽  
pp. 1170-1174
Author(s):  
B. Sreenivasa Theja ◽  
Siddharth Kumar Singh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Boundary Conditions ◽  
Life Span ◽  
Rear Axle ◽  
Stress Strain ◽  
Element Analysis ◽  
The Real ◽  
Various Boundary Conditions ◽  
The Finite Element Analysis

The design of structural modeling is usually based on the different geometric function. Since every component has a definite life span, it is necessary to calculate its core parameters. To find the life span of component, the component must be as input parameter to the Finite Element Analysis. The Finite Element Analysis is nothing but a numerical method for solving Engineering and Mathematical problems. The Analysis of the “Rear Axle Casing of Tractor” using cast iron material with special grade “SG 500” for already existing model, taken in the real time is done by using “ANSYS”. The stress, strain, deformation analysis of the component is done by giving various boundary conditions. These analyzed results help to redesign the rear casing of tractor. The redesigning of rear axel casing of tractor is done using “PRO/E”. During redesigning the component, various criteria’s taken in the real field must be taken into an account. The analysis of the redesigned model is done by giving various boundary conditions for both materials ‘SG 500” and “SG 200”. Then the stress, strain, deformation, structural supports, structural results are evaluated and also cores, dies and patterns are generated and hence the redesigned rear axel casing of tractor is found to be in safer mode. And also the better material for the rear axle casing is given, by comparing the above mentioned materials.

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