scholarly journals Research on Shock Acceleration Limit of an Ultra-Stable Optical Cavity for Space Applications Based on the Finite Element Methodology

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 998
Author(s):  
Guanjun Xu ◽  
Dongdong Jiao ◽  
Long Chen ◽  
Linbo Zhang ◽  
Jun Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Optical Cavity ◽  
Vertical Direction ◽  
Hole Diameter ◽  
Horizontal Direction ◽  
Shock Acceleration ◽  
Space Applications ◽  
Optical Cavities ◽  
Rocket Launch ◽  
Finite Element Methodology

Ultra-stable optical cavities (USOCs) as fragile precision instruments have many important applications in space. In order to protect them from being damaged during a rocket launch, we analyzed a USOC by means of finite element methodology. The shock acceleration limits that the USOC can withstand in different directions and under various conditions are given. To increase the shock acceleration limit, the midplane thickness and the fixed hole diameter should be selected to be as high as possible. It is worth noting that the launch direction of the USOC should be selected as the horizontal direction, for which the shock acceleration limit that the USOC can withstand is approximately two times that of the vertical direction. In this paper, results provide guidance for the design of USOCs for space applications, especially the design to prevent the damage caused by a shock. The method could then be applied to other space optical cavities, providing a tool to improve the effect of shock at high accelerations.

Numerical Analysis of a Shallow-Buried Portal in Expressway Tunnel with Weak Rockmass

2012 ◽  
Vol 256-259 ◽  
pp. 1369-1372
Author(s):  
Pan Ke Gao ◽  
Yong Li Xie ◽  
Heng Bin Wu
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Element Simulation ◽  
Vertical Direction ◽  
Surrounding Rock ◽  
Horizontal Direction ◽  
Element Simulation ◽  
Key Factor ◽  
Mountain Tunnels ◽  
Unsymmetrical Loading

Aiming at the problems in construction for a shallow-buried and unsymmetrical loading portal in Banzhulin Tunnel in Yu-Xiang expressway, the finite element simulation were carried on to study the behavior for bench excavation method. Main results of numerical analysis as follows:the displacement of surrounding rock of right tunnel(as AR)at the horizontal direction is large and may larger than that of the left tunnel(as AL) at the vertical direction,and the largest deformation is 22.63mm,occuring at the key point DL. Compared with the data of monitoring measurement, the correctness of this simulation was proved.The behavior for deformation and stress of mountain tunnels as Banzhulin is basically mastered,and the displacement of rockmass is the key factor in tunnelling.

Designing and Simulation of a Multi-Direction Tiny Force Switch

2012 ◽  
Vol 468-471 ◽  
pp. 895-898
Author(s):  
Tao Huang ◽  
Zhuo Qing Yang ◽  
Gui Fu Ding ◽  
Xiao Lin Zhao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Vertical Direction ◽  
Horizontal Direction ◽  
Surface Processing ◽  
Element Analysis ◽  
Movable Electrode ◽  
Fixed Electrode ◽  
Test Result

This paper describes the designing and producing of a multi-direction tiny force switch, which is based on the technology of micro-surface processing on privative silicon. The switch is mainly formed by shore, overhanging spring, movable electrode and fixed electrode. Its’ structure material is Ni. The parameters of switch are confirmed by doing finite-element analysis with ANSYS. And rigidities of structure both on horizontal direction and vertical direction are analyzed by using ANSYS to ensure that the uniformity of switch rigidity is qualified. After producing the switch, the rigidity of switch is tested by using bonding tester. The test result shows that the rigidity is almost qualified with requirements.

scholarly journals Numerical investigation into the stability of earth dam slopes considering the effects of cavities

2019 ◽  
Vol 37 (4) ◽  
pp. 1397-1421
Author(s):  
Hawraa Alateya ◽  
Alireza Ahangar Asr
Keyword(s):  
Finite Element ◽  
Vertical Direction ◽  
Simulation Models ◽  
Horizontal Direction ◽  
Earth Dam ◽  
Earth Dams ◽  
Content Type ◽  
Finite Element Software ◽  
Stability Of Slopes ◽  
The Stability

Purpose This study is an attempt to estimate the influence of the presence of cavities on the stability of slopes in earth dams under rapid drawdown conditions. The purpose of this paper is to study the influence of different factors, such as the diameter and location of cavities, in addition to their existence effects. Design/methodology/approach A series of finite element simulation models were developed using PLAXIS 2D finite element software to analyse the stability of slopes in earth dams while considering various effects from cavities in the subsoil under rapid drawdown conditions. Findings The results indicated that the presence of cavities and an increase in the diameter of cavities decreased the stability of the upstream face dramatically for all examined locations in a horizontal direction; however, this effect was less on the downstream side. The results also showed that variations in the location of cavities in the horizontal direction have a greater effect on the stability than those in the vertical direction. The results revealed that increasing shear strength parameters of embankment does not reduce the influence of cavities on stability when those cavities are in critical locations. Originality/value A numerical model has been developed to simulate the effects of cavities on the stability of slopes in water-retaining structures/earth dams. The stability of earth dam slopes on upstream and downstream sides under rapid drawdown conditions considering various cavity effects, including their existence, diameter and location, were numerically analysed.

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

scholarly journals Comparison of one versus two maxillary molars distalization with iPanda: a finite element analysis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Kamontip Sujaritwanid ◽  
Boonsiva Suzuki ◽  
Eduardo Yugo Suzuki
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Alveolar Bone ◽  
Vertical Direction ◽  
Minimal Amount ◽  
Element Analysis ◽  
Molar Distalization ◽  
Second Molar ◽  
Maxillary Molars ◽  
Displacement Patterns

Abstract Background The purpose of this study was to compare the stress distribution and displacement patterns of the one versus two maxillary molars distalization with iPanda and to evaluate the biomechanical effect of distalization on the iPanda using the finite element method. Methods The finite element models of a maxillary arch with complete dentition, periodontal ligament, palatal and alveolar bone, and an iPanda connected to a pair of midpalatal miniscrews were created. Two models were created to simulate maxillary molar distalization. In the first model, the iPanda was connected to the second molar to simulate a single molar distalization. In the second model, the iPanda was connected to the first molar to simulate “en-masse” first and second molar distalization. A varying force from 50 to 200 g was applied. The stress distribution and displacement patterns were analyzed. Results For one molar, the stress was concentrated at the furcation and along the distal surface in all roots with a large amount of distalization and distobuccal crown tipping. For two molars, the stress in the first molar was 10 times higher than in the second molar with a great tendency for buccal tipping and a minimal amount of distalization. Moreover, the stress concentration on the distal miniscrew was six times higher than in the mesial miniscrew with an extrusive and intrusive vector, respectively. Conclusions Individual molar distalization provides the most effective stress distribution and displacement patterns with reduced force levels. In contrast, the en-masse distalization of two molars results in increased force levels with undesirable effects in the transverse and vertical direction.

Structural Optimization of the Telescopic Boom of a Certain Type of Truck-Mounted Crane

2014 ◽  
Vol 548-549 ◽  
pp. 383-388
Author(s):  
Zhi Wei Chen ◽  
Zhe Cui ◽  
Yi Jin Fu ◽  
Wen Ping Cui ◽  
Li Juan Dong ◽  
...  
Keyword(s):  
Finite Element ◽  
Static Analysis ◽  
Cross Sections ◽  
Optimization Design ◽  
Structural Parameters ◽  
Vertical Direction ◽  
Element Model ◽  
Shape Parameters ◽  
Conventional Design ◽  
Design Variables

Parametric finite element model for a commonly used telescopic boom structure of a certain type of truck-mounted crane has been established. Static analysis of the conventional design configuration was performed first. And then an optimization process has been carried out to minimize the total weight of the telescopic structures. The design variables include the geometric shape parameters of the cross-sections and the integrated structural parameters of the telescopic boom. The constraints include the maximum allowable equivalent stresses and the flexure displacements at the tip of the assembled boom structure in both the vertical direction and the circumferential direction of the rotating plane. Compared with the conventional design, the optimization design has achieved a significant weight reduction of up to 24.3%.

Engineering the sensitivity of macroscopic physical systems to variations in the fine-structure constant

2021 ◽  
Author(s):  
Beata Zjawin ◽  
Marcin Bober ◽  
Roman Ciuryło ◽  
Daniel Lisak ◽  
Michał Zawada ◽  
...  
Keyword(s):  
Fine Structure ◽  
Optical Cavity ◽  
Structure Constant ◽  
Relativistic Effects ◽  
Fine Structure Constant ◽  
Sensitivity Factor ◽  
Optical Cavities ◽  
Physical Systems ◽  
Heavy Atoms ◽  
Nuclear Transitions

Abstract Experiments aimed at searching for variations in the fine-structure constant α are based on spectroscopy of transitions in microscopic bound systems, such as atoms and ions, or resonances in optical cavities. The sensitivities of these systems to variations in α are typically on the order of unity and are fixed for a given system. For heavy atoms, highly charged ions and nuclear transitions, the sensitivity can be increased by benefiting from the relativistic effects and favorable arrangement of quantum states. This article proposes a new method for controlling the sensitivity factor of macroscopic physical systems. Specific concepts of optical cavities with tunable sensitivity to α are described. These systems show qualitatively different properties from those of previous studies of the sensitivity of macroscopic systems to variations in α, in which the sensitivity was found to be fixed and fundamentally limited to an order of unity. Although possible experimental constraints attainable with the specific optical cavity arrangements proposed in this article do not yet exceed the present best constraints on α variations, this work paves the way for developing new approaches to searching for variations in the fundamental constants of physics.

Numerical Simulation of a Jumper Conveying Slurry for Deep-Sea Mining

2021 ◽  
Author(s):  
Marcio Yamamoto ◽  
Tomo Fujiwara ◽  
Joji Yamamoto ◽  
Sotaro Masanobu
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Dynamic Analysis ◽  
Internal Pressure ◽  
Deep Sea ◽  
Petroleum Industry ◽  
Vertical Direction ◽  
Internal Flow ◽  
Horizontal Direction ◽  
Viscous Pressure

Abstract One key technology for Deep-Sea Mining is the riser system. The riser is already a field-proven technology in the Petroleum Industry. However, several differences exist between a petroleum production riser and a riser for Deep-Sea Mining, mainly related to the internal flow. The ore-slurry has a larger density than the hydrocarbons and shall be pumped with a much higher flowrate. The current software tools for riser’s dynamic analysis may include the internal fluid hydrostatic pressure and the centrifugal and Coriolis forces imposed by the bent pipe’s internal flow. However, the internal pressure drop is not calculated. The internal pressure alters the pipe’s effective tension and can alter the pipe’s bending moment changing its mechanical behavior. This article describes a computational script’s development to run embedded in a commercial software for riser’s dynamic analysis. Our script calculates the internal viscous pressure drop along with the jumper. This pressure is then converted into wall axial tension (buckling) and imposed on each node of the jumper’s numerical model. Each simulation case was calculated twice with and without the internal flow viscous pressure drop. The comparison with experimental data revealed that the jumper’s average position has a good agreement among all cases. However, the amplitude caused by the top oscillation showed some discrepancies. Experimental data has the highest amplitude in the horizontal direction, while the simulation without viscous pressure calculation had the smallest. The simulation with our embedded script had intermediary amplitude in the horizontal direction. The vertical direction amplitudes have the same behavior for all cases, but the experimental data showed the highest amplitude.

Analysis of Wrinkled Membranes Bounded With Macro-Fiber Composite (MFC) Actuators

2010 ◽  
Author(s):  
Alireza Doosthoseini ◽  
Armaghan Salehian ◽  
Matthew Daly
Keyword(s):  
Finite Element ◽  
Fiber Composite ◽  
The Other ◽  
Horizontal Direction ◽  
Finite Element Code ◽  
Rectangular Shape ◽  
Macro Fiber Composite

In this paper we focus on a study which involves quantifying the effects of Macro Fiber Composite (MFC) actuators on the pattern and magnitude of wrinkles in a membrane when exposed to various loadings. An ABAQUS finite element code is employed for this research. The membrane in this study has a rectangular shape which is clamped at one edge and is free to move in the horizontal direction at the other edge. MFC actuators are bounded to the membrane to make a bimorph configuration.

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