scholarly journals Analysis and Design of a Novel Concept Gasket to Improve the Reliability of the Balanced Armature Receiver Used in Earphones

2019 ◽  
Vol 9 (18) ◽  
pp. 3661
Author(s):  
Zhi-Xiong Jiang ◽  
Jun-Hyung Kim ◽  
Yuan-Wu Jiang ◽  
Dan-Ping Xu ◽  
Sang-Moon Hwang
Keyword(s):  
Harmonic Distortion ◽  
Von Mises Stress ◽  
Shock Absorption ◽  
Analysis And Design ◽  
Absorption Performance ◽  
Novel Concept ◽  
Von Mises ◽  
External Forces ◽  
Drop Impacts ◽  
Drop Impact Test

Currently, balanced armature (BA) receivers are frequently used in earphones, owing to their small size and superior sound quality. However, the reliability of BA receiver earphones has become a considerable challenge, as they easily fail when subjected to external forces, especially during drop impacts. In addition, the original gasket cannot protect the BA receiver well. Therefore, this article focuses on improving the reliability of BA receiver earphones by designing a novel concept for the gasket. Based on a simplified model and analysis methods, the maximum von Mises stress on the armature with different drop directions and the maximum von Mises stress point must first be determined. The gasket was divided into two parts, one for linking and the other for shock absorption. This article focused on the design of the shock absorption structure. A novel concept gasket was proposed, and the analysis results showed that the gasket improved the shock absorption performance. For demonstrating the validity of the shock absorption performance of the novel concept gasket, three confirmatory experiments were performed: the drop impact test, X-ray photography, and sound performance, which included the sound pressure level and total harmonic distortion. The analysis results were experimentally verified.

INCREASING THE HEIGHT OF A GUYED STEEL STACK WHICH IS SUPPORTED ON AN INDUTRIAL BUILDING

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Roman Okelo ◽  
Bradford Russell
Keyword(s):  
Von Mises Stress ◽  
Industrial Building ◽  
Chemical Waste ◽  
Industrial Facilities ◽  
Analysis And Design ◽  
Finite Element Software ◽  
Standard Code ◽  
New Guidelines ◽  
Von Mises ◽  
Construction Documents

The paper studied the rehabilitation and increase in height of an existing 30 ft tall, industrial, guyed steel stack, which was built around 1977. The stack is supported on an industrial building. Stacks are an essential part of the industrial facilities. They allow the discharge of chemical waste gases from industries to the atmosphere, under stringent pollution control guidelines. The height of the stack is increased by 40 ft to comply with the new guidelines. Analytical and numerical simulations were performed using MecaStack software (local model) and SAP2000 V.20 software (global model). Analysis and design are based on the ASME STS-1-2016 standard code. Discontinuity around the manhole at the bottom of the stack is investigated with SAP2000 V.20 finite element software. Results in terms of principle stresses, and Von-Mises stress, were used to prepare recommendations, repair and construction documents for the project.

The Evaluation of Absorption Performance of Magneto-Rheological (MR) Elastomer

2015 ◽  
Vol 1095 ◽  
pp. 483-489
Author(s):  
Kwang Hee Lee ◽  
Kyung Sik Jung ◽  
Chul Hee Lee
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Impact Test ◽  
Impact Load ◽  
Time Duration ◽  
Shock Absorption ◽  
Absorption Performance ◽  
Magneto Rheological ◽  
Drop Impact Test ◽  
The Magnetic Field

This study examines the relation between the thickness of a specimen and the weight of an impactor for evaluating the shock absorption performance of magneto-rheological (MR) elastomers with and without a magnetic field. The shock absorption performance can be evaluated by calculating impact energy. The MR elastomer is a smart material and its mechanical properties change under the influence of a magnetic field. The drop impact test is performed to evaluate the amount of shock absorption of the MR elastomer for each test condition. Tests are also performed by varying the magnetic field during impact to improve the shock absorption performance of the MR elastomer, which is related to impact load. The results show a better shock absorption performance with a thicker MR elastomer, lighter impactor, and without a magnetic field. Also, the magnitude of impact and the time duration for stabilization are improved when the magnetic field is varied during the test.

Distortion Energy Based Design of Structures Under Random Excitations

1997 ◽  
Author(s):  
Mu-Tsang Chen
Keyword(s):  
Finite Element ◽  
Stress Responses ◽  
Random Vibration ◽  
Safety Margin ◽  
Von Mises Stress ◽  
Design Strength ◽  
Analysis And Design ◽  
Distortion Energy ◽  
Von Mises ◽  
Energy Based Design

Abstract Random vibration analysis (RVA) of structural systems is a rapidly growing branch of engineering mechanics. The theory of random vibration is central to the analysis and design of structures in a variety of engineering fields. In recent years, RVA in conjunction with finite element methods has been available in several commercial computer-aided-engineering software, such as ANSYS, NASTRAN, etc. The finite element-based RVA is being widely adopted for computing stochastic responses, such as displacements, stresses and strains in terms of statistical quantities, i.e., root-mean-square responses. However, these statistical responses from RVA are limited to Cartesian responses which depend on the coordinate system of use. In structural design, a failure criterion using distortion energy known as the von Mises theory is more appropriate and of interest in this paper. The statistics of von Mises stress can not be obtained in terms of the statistics of Cartesian stresses. Simulation-based von Mises stress responses corresponding to a covariance matrix of Cartesian stresses are used to perform scatter and failure analyses. Based on a sufficient number of stress samples, a probability distribution of von Mises stress response may be obtained. Given a specified design criterion, statistical moments of safety margin as well as a safety index can be computed. In addition, a required design strength corresponding to a desired probability of failure can be provided in this study.

Qualification of Water-Filled Tank due to Tornado Missile Impact

2016 ◽  
Author(s):  
Timothy A. Schmitt ◽  
Taha Al-Shawaf ◽  
Syed M. Rahman ◽  
Angelo Cristobal
Keyword(s):  
Material Properties ◽  
Impact Analysis ◽  
Impact Angle ◽  
Von Mises Stress ◽  
Empirical Formulas ◽  
Element Analysis ◽  
Fukushima Accident ◽  
Analysis And Design ◽  
Lower Elevation ◽  
Von Mises

As part of the post-Fukushima accident scenario, the qualification of a water-filled cylindrical tank subjected to tornado missile impact was required to ensure the availability of water inventory in the tank to mitigate the post-accident effects. Most of the classical tornado missile impact analysis and design involves using empirical formulas that have been developed based on tests. It is recognized that water backed structures provide additional resistance to perforation of the missile due to the mass and properties of the water. Therefore, a finite element analysis was used to qualify the tank for two controlling postulated missiles, namely, 2 ½” diameter schedule 40 pipe and bolted wood decking. The location on the tank for the missile impact, angle of impact and orientation of the missile were selected to develop the most critical response. The analysis was performed using the LS-DYNA computer program. The true stress-strain material properties were used for both the tank material and the missile types. These material properties were given a bilinear elastic-plastic curve. It was determined that, even if an impact at the thinnest section at the top of the tank occurs and the missile penetrates, the remaining inventory of water in the tank will be sufficient to mitigate the needs for a post-Fukushima scenario. Impact on the lower elevation of the tank was investigated for any potential failure or tearing of the tank wall. The maximum of equivalent (Von Mises) stress, shear stress, and plastic strain were calculated. The results show that these values are less than the limiting values with additional available margin. Consequently the analysis shows that the tank will survive a hit in the lower portions, and the water inventory of the tank is sufficient to mitigate the effect of a post-Fukushima scenario should a missile penetrate the thinner, upper section of the tank.

scholarly journals Study on Impeller Fracture Model Based on Vibration Characteristics and Fractal Theory

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Xiaolong Zhang ◽  
Ruishan Yuan ◽  
Yonghui Xie
Keyword(s):  
Failure Modes ◽  
Fractal Theory ◽  
Failure Process ◽  
Three Dimensional ◽  
Element Model ◽  
Von Mises Stress ◽  
Strong Nonlinearity ◽  
Von Mises ◽  
External Forces ◽  
Three Dimensional Finite Element

During the operation of centrifugal compressor, failure easily occurs in the presence of complicated external forces. The failure process characterizes with strong nonlinearity, and hence it is difficult to be described by conventional methods. In this paper, firstly, the cracks in different positions are described using crack fractal theory. The basic failure modes of the impeller are summarized. Secondly, a three-dimensional finite element model of the impeller is constructed. Then the von Mises stress under the centrifugal force is calculated, and the corresponding impeller failure process is simulated by “element life and death technology” in ANSYS. Finally, the impeller failure mechanism is analyzed. It can be found that the static stress is not the main cause of the impeller failure, and the dynamic characteristics of the impeller are not perfect because of the pitch vibration modes which appeared in the investigated frequency range. Meanwhile, the natural frequency of the impeller also cannot avoid the frequency of the excitation force.

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

2020 ◽  
Author(s):  
Nurullah Türker ◽  
Hümeyra Tercanlı Alkış ◽  
Steven J Sadowsky ◽  
Ulviye Şebnem Büyükkaplan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Good Prognosis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Group Function ◽  
Occlusal Contact ◽  
Maximum Deformation ◽  
Contact Points ◽  
Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

The Influence of Loading Position in A Priori High Stress Detection using Mode Superposition

2020 ◽  
Vol 1 (1) ◽  
pp. 93-102
Author(s):  
Carsten Strzalka ◽  
◽  
Manfred Zehn ◽  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
A Priori ◽  
High Stress ◽  
Von Mises Stress ◽  
Detailed Knowledge ◽  
Variable Loading ◽  
Numerical Effort ◽  
Von Mises

For the analysis of structural components, the finite element method (FEM) has become the most widely applied tool for numerical stress- and subsequent durability analyses. In industrial application advanced FE-models result in high numbers of degrees of freedom, making dynamic analyses time-consuming and expensive. As detailed finite element models are necessary for accurate stress results, the resulting data and connected numerical effort from dynamic stress analysis can be high. For the reduction of that effort, sophisticated methods have been developed to limit numerical calculations and processing of data to only small fractions of the global model. Therefore, detailed knowledge of the position of a component’s highly stressed areas is of great advantage for any present or subsequent analysis steps. In this paper an efficient method for the a priori detection of highly stressed areas of force-excited components is presented, based on modal stress superposition. As the component’s dynamic response and corresponding stress is always a function of its excitation, special attention is paid to the influence of the loading position. Based on the frequency domain solution of the modally decoupled equations of motion, a coefficient for a priori weighted superposition of modal von Mises stress fields is developed and validated on a simply supported cantilever beam structure with variable loading positions. The proposed approach is then applied to a simplified industrial model of a twist beam rear axle.

scholarly journals Numerical Investigation of the Deformable Porous Media Treated by the Intermittent Microwave

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 757
Author(s):  
Tianyi Su ◽  
Wenqing Zhang ◽  
Zhijun Zhang ◽  
Xiaowei Wang ◽  
Shiwei Zhang
Keyword(s):  
Porous Media ◽  
Heat Transport ◽  
Liquid Water ◽  
Von Mises Stress ◽  
Temperature Deformation ◽  
Local Maxima ◽  
Whole Process ◽  
Surface Areas ◽  
Pulse Ratio ◽  
Von Mises

A 2D axi-symmetric theoretical model of dielectric porous media in intermittent microwave (IMW) thermal process was developed, and the electromagnetic energy, multiphase transport, phase change, large deformation, and glass transition were taken into consideration. From the simulation results, the mass was mainly carried by the liquid water, and the heat was mainly carried by liquid water and solid. The diffusion was the dominant mechanism of the mass transport during the whole process, whereas for the heat transport, the convection dominated the heat transport near the surface areas during the heating stage. The von Mises stress reached local maxima at different locations at different stages, and all were lower than the fracture stress. A material treated by a longer intermittent cycle length with the same pulse ratio (PR) tended to trigger the phenomena of overheat and fracture due to the more intense fluctuation of moisture content, temperature, deformation, and von Mises stress. The model can be extended to simulate the intermittent radio frequency (IRF) process on the basis of which one can select a suitable energy source for a specific process.

scholarly journals Finite Element Analysis of Composite Repair for Damaged Steel Pipeline

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 301
Author(s):  
Jiaqi Chen ◽  
Hao Wang ◽  
Milad Salemi ◽  
Perumalsamy N. Balaguru
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Hoop Stress ◽  
Pipe Wall ◽  
Von Mises Stress ◽  
Repair System ◽  
Composite Repair ◽  
Steel Pipeline ◽  
Von Mises ◽  
Infill Material

Carbon fiber reinforced polymer (CFRP) matrix composite overwrap repair systems have been introduced and accepted as an alternative repair system for steel pipeline. This paper aimed to evaluate the mechanical behavior of damaged steel pipeline with CFRP repair using finite element (FE) analysis. Two different repair strategies, namely wrap repair and patch repair, were considered. The mechanical responses of pipeline with the composite repair system under the maximum allowable operating pressure (MAOP) was analyzed using the validated FE models. The design parameters of the CFRP repair system were analyzed, including patch/wrap size and thickness, defect size, interface bonding, and the material properties of the infill material. The results show that both the stress in the pipe wall and CFRP could be reduced by using a thicker CFRP. With the increase in patch size in the hoop direction, the maximum von Mises stress in the pipe wall generally decreased as the maximum hoop stress in the CFRP increased. The reinforcement of the CFRP repair system could be enhanced by using infill material with a higher elastic modulus. The CFRP patch tended to cause higher interface shear stress than CFRP wrap, but the shear stress could be reduced by using a thicker CFRP. Compared with the fully bonded condition, the frictional interface causes a decrease in hoop stress in the CFRP but an increase in von Mises stress in the steel. The study results indicate the feasibility of composite repair for damaged steel pipeline.

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