Coupling Effect Analysis of 3D Interior Structural-Acoustic Problems Using Wave Based Method

2011 ◽  
Vol 228-229 ◽  
pp. 526-531
Author(s):  
Cai Xia You ◽  
Guang De Zhang
Keyword(s):  
Arbitrary Shape ◽  
Coupling Effect ◽  
Three Dimensional ◽  
Cavity Depth ◽  
Effect Analysis ◽  
Acoustic Coupling ◽  
Acoustic Cavity ◽  
Prediction Technique ◽  
Out Of Plane ◽  
Plane Displacement

This paper describes the basic concept of the new technique for the modeling of the structural-acoustic coupling between the pressure field in an acoustic cavity with arbitrary shape and the out-of-plane displacement of a flat plate with arbitrary shape. It is illustrated through a three-dimensional validation example that the new prediction technique yields a high accuracy. The effect of the cavity depth and the coupling interface area on the strength of mutual coupling interaction are discussed in detail.

Mechanism of the Transition From In-Plane Buckling to Helical Buckling for a Stiff Nanowire on an Elastomeric Substrate

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
Youlong Chen ◽  
Yong Zhu ◽  
Xi Chen ◽  
Yilun Liu
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Stretchable Electronics ◽  
Buckling Mode ◽  
Design And Optimization ◽  
Out Of Plane ◽  
Plane Direction ◽  
Plane Displacement ◽  
Helical Buckling ◽  
Selection Of

In this work, the compressive buckling of a nanowire partially bonded to an elastomeric substrate is studied via finite-element method (FEM) simulations and experiments. The buckling profile of the nanowire can be divided into three regimes, i.e., the in-plane buckling, the disordered buckling in the out-of-plane direction, and the helical buckling, depending on the constraint density between the nanowire and the substrate. The selection of the buckling mode depends on the ratio d/h, where d is the distance between adjacent constraint points and h is the helical buckling spacing of a perfectly bonded nanowire. For d/h > 0.5, buckling is in-plane with wavelength λ = 2d. For 0.27 < d/h < 0.5, buckling is disordered with irregular out-of-plane displacement. While, for d/h < 0.27, buckling is helical and the buckling spacing gradually approaches to the theoretical value of a perfectly bonded nanowire. Generally, the in-plane buckling induces smaller strain in the nanowire, but consumes the largest space. Whereas the helical mode induces moderate strain in the nanowire, but takes the smallest space. The study may shed useful insights on the design and optimization of high-performance stretchable electronics and three-dimensional complex nanostructures.

Analytical studies on Mode III fracture in flexoelectric solids

2021 ◽  
pp. 1-32
Author(s):  
Xinpeng Tian ◽  
Mengkang Xu ◽  
Haiyang Zhou ◽  
Qian Deng ◽  
Qun Li ◽  
...  
Keyword(s):  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Expansion Method ◽  
Gradient Field ◽  
J Integral ◽  
Mode Iii ◽  
Flexoelectric Effect ◽  
Local Strength ◽  
Out Of Plane ◽  
Plane Displacement

Abstract Due to the stress concentration near crack tips, strong flexoelectric effect would be observed there, which might lead to new applications of flexoelectricity in material science and devices. However, different from the flexoelectric effect in cantilever beams or truncated pyramids, at the crack tip, multiple components of strain gradients with nonuniform distribution contribute to the flexoelectric effect, which makes the problem extremely complex. In this paper, with the consideration of both direct and converse flexoelectricity, the electromechanical coupling effect around the tip of a Mode III crack is studied analytically. Based on the Williams' expansion method, the displacement field, polarization field, strain gradient field along with the actual physical stresses field are solved. A path independent J-integral for Mode III cracks in flexoelectric solids is presented. Our results indicate that the existence of flexoelectricity leads to a decrease of both the J-integral and the out-of-plane displacement in Mode III cracks, which means that the flexoelectric effect around the tip of Mode III cracks enhances the local strength of materials.

Out-of-Plane Displacement Derivative Measurements Using Interferometric Strain/Slope Gage

1996 ◽  
Vol 63 (4) ◽  
pp. 1033-1038 ◽  
Author(s):  
Keyu Li
Keyword(s):  
Coupling Effect ◽  
Controlled System ◽  
High Deformation ◽  
Out Of Plane ◽  
Computer Controlled ◽  
Fringe Patterns ◽  
Photodiode Arrays ◽  
Plane Displacement ◽  
Deformation Gradients ◽  
Derivatives Of

An optical method originally developed for measuring derivatives of in-plane displacements is redefined to measure derivatives of out-of-plane displacements. The technique is based on interference of laser beams reflected and diffracted from two microindentations closely depressed on a specimen surface. As in-plane and out-of-plane displacements cause the microindentations to move relatively to each other, the two interference fringe patterns change accordingly. Movement of the interference fringes is monitored with linear photodiode arrays and analyzed via a computer-controlled system that allows simultaneous measurements of the in-plane and out-of-plane displacement derivatives. The technique is referred to as the interferometric strain/slope gage (ISSG). Having short gage length (˜100 μm), the technique is unique for measurements of high deformation gradients and for applications in complex geometries. Its principle as well as an experimental validation of measuring bending strains/stresses and deflection slopes in a cantilever beam is presented. The experiment shows that both the first-order and second-order derivatives of out-of-plane displacements can be obtained. Measurement sensitivities to in-plane and out-of-plane rigid-body motions are systematically investigated. The technique can be potentially extended to measure large deflection angles. The derived governing equations indicate a coupling effect between the in-plane and out-of-plane components. The associated instrumentation for data acquisition and analysis is described in great detail.

A Comparison Between the Accuracy of Two-Dimensional and Three-Dimensional Strain Measurements

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Niranjan Desai ◽  
Joel Poling ◽  
Gregor Fischer ◽  
Christos Georgakis
Keyword(s):  
Structural Damage ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Image Correlation ◽  
3D Measurement ◽  
Two Dimensional ◽  
Strain Measurements ◽  
Out Of Plane ◽  
2D System ◽  
Plane Displacement

This investigation determined the effect of specimen out-of-plane movement on the accuracy of strain measurement made applying two-dimensional (2D) and three-dimensional (3D) measurement approaches using the representative, state-of-the-art digital image correlation (DIC)-based tool ARAMIS. DIC techniques can be used in structural health monitoring (SHM) by measuring structural strains and correlating them to structural damage. This study was motivated by initially undetected damage at low strains in connections of a real-world bridge, whose detection would have prevented its propagation, resulting in lower repair costs. This study builds upon an initial investigation that concluded that out-of-plane specimen movement results in noise in DIC-based strain measurements. The effect of specimen out-of-plane displacement on the accuracy of strain measurements using the 2D and 3D measurement techniques was determined over a range of strain values and specimen out-of-plane displacements. Based upon the results of this study, the 2D system could measure strains as camera focus was being lost, and the effect of the loss of focus became apparent at 1.0 mm beam out-of-plane displacement while measuring strain of the order of magnitude of approximately 0.12%. The corresponding results for the 3D system demonstrate that the beam out-of-plane displacement begins to affect the accuracy of the strain measurements at approximately 0.025% strain for all magnitudes of out-of-plane displacement, and the 3D ARAMIS system can make accurate strain measurements at up to 2.5 mm amplitude at this strain. Finally, based upon the magnitudes of strain and out-of-plane displacement amplitudes that typically occur in real steel bridges, it is advisable to use the 3D system for SHM of stiff structures instead of the 2D system.

Design Optimization of a Novel, Large-Displacement, Multi-Axis, Silicon/Polymer Hybrid Actuator for Micro Optics

2003 ◽  
Author(s):  
Yi-Chung Tung ◽  
Jeong-Gil Kim ◽  
Katsuo Kurabayashi
Keyword(s):  
Design Optimization ◽  
Parametric Design ◽  
Actuation Voltage ◽  
Three Dimensional ◽  
Element Analysis ◽  
Optical Scanners ◽  
Polymer Hybrid ◽  
Out Of Plane ◽  
Micro Optics ◽  
Plane Displacement

This paper investigates a novel silicon/polymer hybrid MEMS actuator and reports on its design optimization. The actuator, incorporating a three-dimensional poly(dimethylsiloxane) (PDMS) flexural microstructure, is designed to generate multi-axis displacement of motion. This work develops a four-bar linkage model for parametric design of the actuator and validates it using finite element analysis (FEA). The optimization of the device geometry is performed using Genetic Algorithm (GA) such that the resulting out-of-plane displacement can achieve a maximum value under several design constrains due to fabrication and operation limitations. The out-of-plane displacement of the optimized actuator structure is calculated to be as large as 60 μm at 50 V input actuation voltage. Due to its unique mechanical and optical material properties, the PDMS microstructure allows the proposed device to achieve actuation performances suitable for a wide variety of micro-optics applications, including micro optical scanners, dynamic-focus micro lens holders, and mechanically flexible optical gratings.

scholarly journals Sensor Integrated Load-Bearing Structures: Measuring Axis Extension with DIC-Based Transducers

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4104
Author(s):  
Nassr Al-Baradoni ◽  
Peter Groche
Keyword(s):  
Cost Effective ◽  
Image Correlation ◽  
Maximum Deviation ◽  
Single Image ◽  
Eccentric Load ◽  
Load Bearing ◽  
Out Of Plane ◽  
Axis Extension ◽  
Plane Displacement ◽  
Imaging Sensor

In this paper we present a novel, cost-effective camera-based multi-axis force/torque sensor concept for integration into metallic load-bearing structures. A two-part pattern consisting of a directly incident and mirrored light beam is projected onto the imaging sensor surface. This allows the capturing of 3D displacements, occurring due to structure deformation under load in a single image. The displacement of defined features in size and position can be accurately analyzed and determined through digital image correlation (DIC). Validation on a prototype shows good accuracy of the measurement and a unique identification of all in- and out-of-plane displacement components under multiaxial load. Measurements show a maximum deviation related to the maximum measured values between 2.5% and 4.8% for uniaxial loads ( and between 2.5% and 10.43% for combined bending, torsion and axial load. In the course of the investigations, the measurement inaccuracy was partly attributed to the joint used between the sensor parts and the structure as well as to eccentric load.

Numerical and experimental investigation for enhancing the energy absorption capacity of the novel three-dimensional printed sandwich structures

2021 ◽  
pp. 146442072199749
Author(s):  
H Geramizadeh ◽  
S Dariushi ◽  
S Jedari Salami
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
The Novel ◽  
Energy Absorption Capacity ◽  
Fused Deposition ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Vertical Walls

The current study focuses on designing the optimal three-dimensional printed sandwich structures. The main goal is to improve the energy absorption capacity of the out-of-plane honeycomb sandwich beam. The novel Beta VI and Alpha VI were designed in order to achieve this aim. In the Beta VI, the connecting curves (splines) were used instead of the four diagonal walls, while the two vertical walls remained unchanged. The Alpha VI is a step forward on the Beta VI, which was promoted by filleting all angles among the vertical walls, created arcs, and face sheets. The two offered sandwich structures have not hitherto been provided in the literature. All models were designed and simulated by the CATIA and ABAQUS, respectively. The three-dimensional printer fabricated the samples by fused deposition modeling technique. The material properties were determined under tensile, compression, and three-point bending tests. The results are carried out by two methods based on experimental tests and finite element analyses that confirmed each other. The achievements provide novel insights into the determination of the adequate number of unit cells and demonstrate the energy absorption capacity of the Beta VI and Alpha VI are 23.7% and 53.9%, respectively, higher than the out-of-plane honeycomb sandwich structures.

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