scholarly journals Static repair of multiple cracked beam using piezoelectric patches

2021 ◽  
Vol 43 (2) ◽  
pp. 197-207
Author(s):  
Tran Thanh Hai
Keyword(s):  
Numerical Simulation ◽  
Static Load ◽  
Multiple Cracks ◽  
Bending Moments ◽  
Cracked Beam ◽  
Piezoelectric Patch ◽  
Element Simulation ◽  
Simulation Results ◽  
Moment Load ◽  
Mechanical Moment

This paper addresses the problem of repairing multiple cracked beams subjected to static load using piezoelectric patches. First, the problem is formulated and solved analytically for the case of two cracks that results in ratio of restoring moments produced by employed piezoelectric patches. Since the ratio is dependent only on crack positions but not their depth, the result obtained for case of two cracks has been extended for the case of multiple cracks. This proposition is then validated by finite element simulation where repairing piezoelectric patches are replaced by mechanical moment load equivalent to the restoring bending moments produced by the piezoelectric patches. The excellent agreement between analytical solution and numerical simulation results in case of single and double cracks allows making a conclusion that a piezoelectric patch could productively repair a cracked beam by producing a restoring moment due to its piezoelectricity. Thus, the problem of repairing multiple cracked beam using piezoelectric patches is solved.

scholarly journals Study on Occurrence Mechanism of Coal Pillar in L-Shaped Zone during Fully Mechanized Mining Period and Prevention Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zeng-qiang Yang ◽  
Hong-mei Wang ◽  
De-quan Sun ◽  
Xian-jian Ma ◽  
Ming-bao Xu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Burst ◽  
Dynamic Load ◽  
Static Load ◽  
Coal Pillar ◽  
Simulation Software ◽  
In Situ Investigation ◽  
Simulation Results ◽  
Occurrence Mechanism

In order to study the occurrence mechanism of rock burst in L-shaped zone during a fully mechanized mining period, the No. 705 working face which is located in Baojishan Colliery is taken as a typical engineering background. By means of in situ investigation, theoretical analysis, numerical simulation, in situ tests, and relevant monitoring methods, the occurrence mechanism of rock burst and corresponding prevention technology are studied. The results show that a coal pillar with some confining pressure in the L-shaped zone is established by FLAC3D numerical simulation software, and the numerical simulation results indicate that the change in static load has a greater effect than dynamic load on coal pillar unstable failure; the static load plays a role in storing energy, and dynamic load plays a role in inducing rock burst; the bolt-mesh-cable support and high-pressure water jet unloading combined technology is put forward to prevent rock burst in roadways, and the numerical simulation results show that stress distribution of surrounding rock meets the model of strong-soft-strong (3S) structure, and the moment distribution is reasonable. In the follow-up mining, a limit value of coal fines is used to determine that this measure is a reasonable method to prevent rock burst. The study conclusions provide theoretical foundation and new guidance for preventing rock burst by synergistic effect technology in roadways.

Dynamic Analysis and Three-Dimensional Finite Element Simulation of Cracked Gear

2007 ◽  
Vol 353-358 ◽  
pp. 1072-1077 ◽  
Author(s):  
Ren Ping Shao ◽  
Xin Na Huang ◽  
Pu Rong Jia ◽  
Wan Lin Guo ◽  
Kaoru Hirota
Keyword(s):  
Fault Diagnosis ◽  
Gear Tooth ◽  
Three Dimensional ◽  
Dynamic Features ◽  
Cracked Beam ◽  
Element Simulation ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Three Dimensional Finite Element ◽  
Good Agreement

A method of damage detection and fault diagnosis for gears is presented based on the theory of elastomeric dynamics according to the theory of cracked beam. It takes an advantage of accurate fault diagnosis of gear body using the change of dynamic features and has some advantages for dynamic design of gear systems.The dynamics characteristics, i.e., natural frequency, vibration shape,dynamic response and so on, due to crack of gear tooth are studied, and the gear dynamics characteristics caused by the position and size of crack are deeply investigated by comparison with FEM. The theoretical analysis results are contrasted with numerical simulation results and shows good agreement with the result by FEM. The proposed method can be used to detect damage and diagnose fault for gear structures and also can be applied to designing dynamic characteristics for gear systems.

Kinetic Modelling and Finite Element Simulation of Natural Rubber Non-Isothermal Vulcanization

2011 ◽  
Vol 306-307 ◽  
pp. 649-653
Author(s):  
Wei Guo Yao ◽  
Yu Xi Jia ◽  
Xiao Xia Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Natural Rubber ◽  
Kinetic Modelling ◽  
Kinetic Equations ◽  
Processing Conditions ◽  
The Finite Element Method ◽  
Incremental Method ◽  
Element Simulation ◽  
Simulation Results

On the basis of kinetic equations constructed in the isothermal vulcanization of natural rubber (NR), a new numerical computation expression of cure degree under non-isothermal conditions is established by the incremental method. The numerical simulation of the vulcanization stage in injection molding processes of NR is performed by the finite element method, and then the time and position-dependent changes in the cure degree are analyzed numerically. The simulation results are consistent with the results described in the previous literatures. The valuable vulcanization characteristics obtained in the simulation will help engineers in the optimum design of processing conditions.

Large-Scale Numerical Simulation of an RC Tunnel Junction Member Using Particle Discretization Scheme FEM

2015 ◽  
Vol 09 (01) ◽  
pp. 1550001 ◽  
Author(s):  
Fangtao Sun ◽  
Seizo Tanaka ◽  
Muneo Hori
Keyword(s):  
Numerical Simulation ◽  
Tunnel Junction ◽  
Large Scale ◽  
Static Load ◽  
Characteristic Functions ◽  
Discretization Scheme ◽  
Multiple Cracking ◽  
Cracking Behavior ◽  
Strain Stress ◽  
Simulation Results

This paper presents a large-scale numerical simulation of a reinforced concrete (RC) tunnel junction member using solid FEM. Particle discretization scheme (PDS), which uses two sets of non-overlapping characteristic functions to discretize displacement field and strain/stress field respectively, is employed to represent the multiple-cracking configurations of concrete. An efficient parallel FE program, called ADVENTURE, is used to implement PDS as well as a reformulated nonlinear concrete constitutive relation. A simplified tunnel junction member, in order to reveal its multiple-cracking behavior under the static load, is studied and the stochastic behavior of cracking is investigated; good agreements are achieved between the simulation results and experimental observations regarding the multiple cracking configurations.

scholarly journals RETRACTED: Based on PRO/E Sheet Metal Product Design Simulation

2011 ◽  
Vol 467-469 ◽  
pp. 1357-1360
Author(s):  
Hong Bo Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Hydrostatic Pressure ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Explicit Finite Element ◽  
Finite Element Software ◽  
Element Simulation ◽  
Simulation Results

Numerical simulation is an effective method for predicting formability of metals, and the use of computer simulation enables a significant increase in the number of tool designs that can be tested before hard tools are manufactured. Based on dynamic explicit finite element software, finite element simulation of sheet metal forming was performed to investigate the applicability of applying hydrostatic pressure on blank in multi point discrete dies. Simulation results show that using the hydrostatic pressure on blank is apposite for the process of multi point discrete dies.

scholarly journals Study on equivalent static method for the analysis of fatigue behavior of reinforced concrete beam

2021 ◽  
Vol 272 ◽  
pp. 02018
Author(s):  
Fangping Liu ◽  
Chen Yu ◽  
Wentao Yi
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Static Load ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
Reinforced Concrete Beam ◽  
Static Method ◽  
Reinforced Concrete Beams ◽  
Simulation Results

In order to analyze the whole process of fatigue behaviours of reinforced concrete beams, an equivalent static analysis method is proposed in this paper. Firstly, the constitutive models based on the degradation of stiffness and strength and the accumulation of residual strain of concrete and reinforcement subjected to fatigue loadings are deduced and established by coupling the uniaxial constitutive model of concrete and the ideal elastic-plastic model of reinforcement under static load. Secondly, based on the similarity of concrete failure under static load and fatigue load, the equivalent relationship between fatigue and static analysis can be constructed by using the concrete residual strain as the equivalent parameter. On this basis, an equivalent static method for the analysis of fatigue behavior of reinforced concrete beam is proposed. At last, three reinforced concrete beams with rectangular section are tested, and the fatigue behaviours are analyzed by the method proposed in this paper. The numerical simulation results are compared with the field test data. The result shows that the numerical simulation results are in good agreement with the experimental results, which verifies the reliability and practicability of the method.

Avalanche Features in Silicon Schottky-FETs in Accordance with Numerical Simulation Results

2006 ◽  
Vol 65 (16) ◽  
pp. 1533-1546
Author(s):  
Yu. Ye. Gordienko ◽  
S. A. Zuev ◽  
V. V. Starostenko ◽  
V. Yu. Tereshchenko ◽  
A. A. Shadrin
Keyword(s):  
Numerical Simulation ◽  
Simulation Results

Numerical Simulation of Tire Sliding Events Involving Impacts with Holes and Bumps

1986 ◽  
Vol 14 (2) ◽  
pp. 125-136 ◽  
Author(s):  
Y. Nakajima ◽  
J. Padovan
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Full Range ◽  
Arbitrary Geometry ◽  
Operating Environments ◽  
Element Simulation ◽  
Simulation Scheme

Abstract This paper extends the finite element simulation scheme to handle the problem of tires undergoing sliding (skidding) impact into obstructions. Since the inertial characteristics are handled by the algorithm developed, the full range of operating environments can be accommodated. This includes the treatment of impacts with holes and bumps of arbitrary geometry.

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

scholarly journals Experiment and simulation about the effect of wear-ring abrasion on the performance of a marine centrifugal pump

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199811
Author(s):  
Wu Xianfang ◽  
Du Xinlai ◽  
Tan Minggao ◽  
Liu Houlin
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Vibration Velocity ◽  
Test Results ◽  
Obvious Effect ◽  
Performance Change ◽  
Pump Test ◽  
Simulation Results ◽  
Axis Passing

The wear-ring abrasion can cause performance degradation of the marine centrifugal pump. In order to study the effect of front and back wear-ring clearance on a pump, test and numerical simulation were used to investigate the performance change of a pump. The test results show that the head and efficiency of pump decrease by 3.56% and 9.62% respectively at 1.0 Qd due to the wear-ring abrasion. Under 1.0 Qd, with the increase of the front wear-ring the vibration velocity at pump foot increases from 0.4 mm/s to 1.0 mm/s. The axis passing frequency (APF) at the measuring points increases significantly and there appears new characteristic frequency of 3APF and 4APF. The numerical simulation results show that the front wear-ring abrasion affects the flow at the inlet of the front chamber of the pump and impeller passage. And the back wear-ring abrasion has obvious effect on the flow in the back chamber of the pump and impeller passage, while the multi-malfunction of the front wear-ring abrasion and back wear-ring abrasion has the most obvious effect on the flow velocity and flow stability inside pump. The pressure pulsation at Blade Passing Frequency (BPF) of the three schemes all decrease with the increase of the clearance.

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