Design of Cylindrical Metamaterial Invisible Cloak with Non-Singular Electromagnetic Tensors

2014 ◽  
Vol 1082 ◽  
pp. 10-13
Author(s):  
Ye Liu ◽  
Zhu Ying Li ◽  
Xiang Yu ◽  
Wen Kang Cao
Keyword(s):  
Finite Element ◽  
Engineering Application ◽  
Simulation Software ◽  
Incoming Wave ◽  
Invisible Cloak ◽  
On Line ◽  
Simulation Results ◽  
Solution Region ◽  
Electromagnetic Perturbation ◽  
Bending Wave

Based on line transformation, cylindrical metamaterial invisible cloak with non-singular electromagnetic tensors is designed. The results of simulation software based on finite element methods (FEM) show that the singularity in the electromagnetic tensors of the cloak has been eliminated, comparing with the cylindrical cloak with ideal tensors. From the simulation results, although there is electromagnetic perturbation in the free-space of the solution region, this cloak exhibits nice electromagnetic invisible performance. The bending wave front is clearly seen when the incoming wave transmits into the cloak region. Because of the non-singular electromagnetic tensors, the designed cloak may have more engineering application than the cloak with idea tensors.

Analysis of In-Plane Equivalent Elastic Modulus of Aluminum Honeycomb Cores Based on Finite Element Method

2013 ◽  
Vol 477-478 ◽  
pp. 1159-1168
Author(s):  
Ming Chen ◽  
Xu Can Xu ◽  
Jin Fei Liu
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Engineering Application ◽  
Volume Element ◽  
Element Analysis ◽  
Aluminum Honeycomb ◽  
Simulation Results ◽  
Honeycomb Cell ◽  
Honeycomb Cores ◽  
Plane Deformations

In order to overcome the low precision of analytic formulas for equivalent elastic modulus of honeycomb, the in-plane deformations of honeycomb are simulated numerically through finite element analysis (FEA) software Ansys. The representative volume element (RVE) is firstly selected and modeled in 3D, according to the repetition of honeycomb cell. Then the deformations of RVE under three different boundary conditions are discussed on several premises. And the equivalent elastic modulus of two specifications of honeycomb from experiments, analytic formulas of Gibson and FEAs simulation results are presented and compared, adequately proving the effectiveness of the above method. Finally, the fitting formulas of equivalent elastic modulus that are convenient for engineering application are proposed by analyzing series of different sizes honeycomb.

scholarly journals Numerical Study on the Explosive Separation of Pyrotechnic Cutter

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Shihui Xiong ◽  
Yaokun Ye ◽  
Yanhua Li ◽  
Yuquan Wen
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Cutting Speed ◽  
Simulation Software ◽  
Cutting Process ◽  
Connecting Rod ◽  
Optimal Distance ◽  
Maximal Speed ◽  
Cutting Effect ◽  
Simulation Results

Pyrotechnic cutters are widely used in the wrapping-band connecting structures of carrier rockets. In this article, a three-dimensional (3D) finite element model of a pyrotechnic cutter is proposed to determine the influence of the explosive dynamic fracture process and the cutter blade acceleration distance on the cutting effect, using AUTODYN finite element simulation software. Numerical simulations of the cutting process reveal that the initial shear speed, the maximal speed, and the speed at which the cutter connects the rod increase linearly with increasing distance between the cutter blade and the cutting board. As the distance increases, the difference between the initial cutting speed and the maximal speed of the cutter gradually decreases and effectively disappears for a distance of 8.5 mm. At this time, the acceleration effect of the gunpowder gas on the cutter is nearly maximal. When the distance between the cutter and the connecting rod is less than 7.5 mm, the cutting time decreases significantly with increasing spacing. For distances between 7.5 mm and 8.5 mm, the distance has little effect on the cutting time as it increases. There is a small increase in the cutting time, and it can be seen that there is an optimal distance between the cutter and the cutting board during the cutting process. The cutting effect is the strongest for this distance. For the cutter studied in this article, the optimal distance was 7.5 mm. In addition, numerical studies were also performed by varying the maximal cutting diameter of the connecting rod of the pyrotechnic cutter. The discrepancy between the simulation results and actual test data was under 10%, and the simulation result for the cut state of the connecting rod was also consistent with the test result. The simulation results in this article can deepen the understanding of the action mechanism and process of the pyrotechnic cutter and reveal the maximal cutting diameter of the connecting rod of the pyrotechnic cutter under different charging conditions. This provides a reference for future cutter design optimization.

An Integrated Environment for Vehicle Dynamics Controls and Integration

2000 ◽  
Author(s):  
Weiwen Deng ◽  
Yong Lee ◽  
Robert Nisonger ◽  
Yuen-kwok Chin
Keyword(s):  
Visual Processing ◽  
Vehicle Dynamics ◽  
Algorithm Design ◽  
Simulation Software ◽  
Development Environment ◽  
Vehicle Simulation ◽  
On Line ◽  
Simulation Results ◽  
User Friendly ◽  
And Control

Abstract This paper provides an overview of VehSim, a PC Windows-based vehicle simulation software for vehicle dynamics, controls and integration. The function and features of VehSim are discussed in general. With its high fidelity, flexibility, portability and user-friendly interfaces, VehSim provides an integrated development environment for engineers to conduct vehicle, especially chassis/driveline modeling, simulation and control algorithm design and to build quick software prototypes to accelerate chassis/driveline controls and integration development. VehSim’s structure, which includes file system, database structure and user graphic interfaces are described. Through its modularized and hierarchical structure, VehSim features great flexibility for engineers to customize their own project needs by developing their own control algorithms or incorporating supplier provided subsystem models and control modules into vehicle dynamics. With the compatibility of VehSim to real-time environment, engineers are able to perform both quick off-line simulation and on-line in-vehicle validation for algorithm development. VehSim also provides built-in user-friendly model preprocessors and postprocessors for engineers to easily build vehicle and/or subsystem models, adjust numerical computation parameters and process the simulation results on line. A 3D solid model based motion animator is also integrated in VehSim for on-line visual processing of simulation results.

Investigation of Die Wear during Fine-Blanking Process of a Kind of Automobile Synchronizer Slipper by FEM and Experiments

2011 ◽  
Vol 314-316 ◽  
pp. 643-652 ◽  
Author(s):  
Fei Yin ◽  
Hua Jie Mao ◽  
Lin Hua ◽  
Zhi Qiang Gu
Keyword(s):  
Finite Element ◽  
Engineering Application ◽  
Fe Model ◽  
Fine Blanking ◽  
The Real ◽  
Die Wear ◽  
Fillet Radius ◽  
Simulation Results ◽  
3D Software ◽  
Blanking Process

In this paper, die wear during fine-blanking process of a kind of automobile synchronizer slipper was investigated based on Finite Element Method (FEM) and experiments. The Finite Element (FE) model to simulate the fine-blanking process of the automobile synchronizer slipper was established on the DEFORM-3D software platform, and Archard's wear model was employed to calculate die wear during the process. Meanwhile, mesh refinement and automatic remeshing technique were used during meshing process of the blanked materials and bottom die in order to achieve high accuracy results of FE simulations and improve the computational efficiency. Simulation results have been verified and show good agreement with the real manufacture. In addition, relationships between die wear and the process parameters during fine-blanking process such as pressure pad force, ejector force, blanking speed, blanking clearance, fillet radius of bottom die as well as hardness of bottom die were investigated, respectively via FEM. The simulation results indicate that die wear is in proportion to the pressure pad force, ejector force, blanking speed and fillet radius of bottom die, while in inverse proportion to the blanking clearance and hardness of bottom die, which will provide a reliable reference for the real manufacture and engineering application.

Experimental and numerical studies on failure and energy absorption of composite thin-walled square tubes under quasi-static compression loading

2020 ◽  
Vol 21 (6) ◽  
pp. 623-634
Author(s):  
Haolei Mou ◽  
Zhenyu Feng ◽  
Jiang Xie ◽  
Jun Zou ◽  
Kun Zhou
Keyword(s):  
Finite Element ◽  
Shell Model ◽  
Energy Absorption ◽  
Failure Mode ◽  
Failure Criterion ◽  
Finite Element Models ◽  
Static Compression ◽  
Compression Loading ◽  
Thin Walled ◽  
Simulation Results

AbstractTo analysis the failure and energy absorption of carbon fiber reinforced polymer (CFRP) thin-walled square tube, the quasi-static axial compression loading tests are conducted for [±45]3s square tube, and the square tube after test is scanned to further investigate the failure mechanism. Three different finite element models, i.e. single-layer shell model, multi-layer shell model and stacked shell mode, are developed by using the Puck 2000 matrix failure criterion and Yamada Sun fiber failure criterion, and three models are verified and compared according to the experimental energy absorption metrics. The experimental and simulation results show that the failure mode of [±45]3s square tube is the local buckling failure mode, and the energy are absorbed mainly by intralaminar and interlaminar delamination, fiber elastic deformation, fiber debonding and fracture, matrix deformation cracking and longitudinal crack propagation. Three different finite element models can reproduce the collapse behaviours of [±45]3s square tube to some extent, but the stacked shell model can better reproduce the failure mode, and the difference of specific energy absorption (SEA) is minimum, which shows the numerical simulation results are in better agreement with the test results.

scholarly journals Investigation of the Thickness Differential on the Formability of Aluminum Tailor Welded Blanks

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 875
Author(s):  
Jie Wu ◽  
Yuri Hovanski ◽  
Michael Miles
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Dome Height ◽  
Tailor Welded Blanks ◽  
Simulation Results

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.

scholarly journals 3D Simulation-Based Acoustic Wave Resonator Analysis and Validation Using Novel Finite Element Method Software

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2715
Author(s):  
Ruth Yadira Vidana Morales ◽  
Susana Ortega Cisneros ◽  
Jose Rodrigo Camacho Perez ◽  
Federico Sandoval Ibarra ◽  
Ricardo Casas Carrillo
Keyword(s):  
Finite Element ◽  
High Performance ◽  
Cloud Services ◽  
3D Simulation ◽  
3D Simulations ◽  
Acoustic Resonators ◽  
Analysis And Design ◽  
Wave Resonator ◽  
Film Bulk ◽  
Simulation Results

This work illustrates the analysis of Film Bulk Acoustic Resonators (FBAR) using 3D Finite Element (FEM) simulations with the software OnScale in order to predict and improve resonator performance and quality before manufacturing. This kind of analysis minimizes manufacturing cycles by reducing design time with 3D simulations running on High-Performance Computing (HPC) cloud services. It also enables the identification of manufacturing effects on device performance. The simulation results are compared and validated with a manufactured FBAR device, previously reported, to further highlight the usefulness and advantages of the 3D simulations-based design process. In the 3D simulation results, some analysis challenges, like boundary condition definitions, mesh tuning, loss source tracing, and device quality estimations, were studied. Hence, it is possible to highlight that modern FEM solvers, like OnScale enable unprecedented FBAR analysis and design optimization.

scholarly journals A Numerical Study on the Combustion Process and Emission Characteristics of a Natural Gas-Diesel Dual-Fuel Marine Engine at Full Load

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1342
Author(s):  
Van Chien Pham ◽  
Jae-Hyuk Choi ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Kyunam Park ◽  
...  
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Simulation Software ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Cylinder Pressure ◽  
Marine Engine ◽  
Full Load ◽  
Simulation Results

This paper presents research on the combustion and emission characteristics of a four-stroke Natural gas–Diesel dual-fuel marine engine at full load. The AVL FIRE R2018a (AVL List GmbH, Graz, Austria) simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both diesel and dual-fuel mode to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed a good agreement with the measured values reported in the engine’s shop test technical data. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 1.7% and 6.75%, while NO, soot, CO, and CO2 emissions were reduced up to 96%, 96%, 86%, and 15.9%, respectively, in the dual-fuel mode in comparison with the diesel mode. The results also show better and more uniform combustion at the late stage of the combustions inside the cylinder when operating the engine in the dual-fuel mode. Analyzing the emission characteristics and the engine performance when the injection timing varies shows that, operating the engine in the dual-fuel mode with an injection timing of 12 crank angle degrees before the top dead center is the best solution to reduce emissions while keeping the optimal engine power.

scholarly journals Longitudinal Guided Wave Inspection of Small-Diameter Elbowed Steel Tubes with a Novel Squirrel-Cage Magnetostrictive Sensor

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Yao Liu ◽  
Xiucheng Liu ◽  
Chehua Yang ◽  
Wenxin Guo ◽  
Bin Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Guided Waves ◽  
Mode Conversion ◽  
Small Diameter ◽  
Longitudinal Mode ◽  
Guided Wave ◽  
Wall Defect ◽  
Squirrel Cage ◽  
Simulation Results ◽  
Magnetostrictive Sensor

In the study, ultrasonic longitudinal mode guided waves were employed to detect defects in elbowed tubes (without welds) with a diameter of 10 mm. Finite element simulation results highlighted that the emitted L(0,1) mode guided waves experienced strong reflection and mode conversion at the elbow region to generate F(1,1) mode, followed by slow and weak F(2,1) mode. The guided wave reflected from the elbow with a through-wall defect was manifested as two overlapped wave packets, which were good indicators of a defective elbow. To conduct L(0,1) mode guided waves inspection on the small-diameter elbowed tubes, a novel tailored squirrel-cage magnetostrictive sensor was employed in the experiment. The new sensor employed the configuration of segmental iron-cobalt strips and small-size permanent magnet arrays. The entire sensor is composed of two identical C-shaped sensor elements and can be recycled and installed conveniently. Experimental results obtained from healthy and defective tubes were consistent with the conclusions obtained from finite element simulations. An artificial through-wall defect at the elbow and a notch defect at the straight part of the tube could be simultaneously detected by L(0,1) mode guided waves through comparing experimental signals with simulation results.

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