A customized fragment for seepage beneath a dam with a vertical wall

2021 ◽  
Author(s):  
Yijiang Zhang ◽  
D.V. Griffiths
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Vertical Wall ◽  
Practical Interest ◽  
Element Analysis ◽  
Anisotropic Permeability ◽  
Flow Problems ◽  
Paper Cover ◽  
Method Of Fragments ◽  
Wide Range

Based on the Method of Fragments for the analysis of steady confined seepage, a customized ‘type E’ fragment is developed, with results presented in the form of charts for the estimation of seepage quantities and exit gradients under embedded water-retaining structures with a vertical cut-off wall. The ‘type E’ fragment is shown to be an extension of previously derived ‘type A and D’ fragments, allowing for both embedment and a cut-off wall. The charts are generated using finite element analysis and cover both isotropic and anisotropic permeability cases. Validation of the fragment is confirmed by comparison with existing Method of Fragments and full finite element analysis. The charts are shown to predict the flow rate and exit gradient more precisely than existing Methods of Fragments. The design charts presented in this paper cover a wide range of confined flow problems of practical interest.

Fabrication and finite element analysis of vibrating parallel film actuator made with cellulose acetate for potential haptic application

2016 ◽  
Vol 230 (15) ◽  
pp. 2720-2727 ◽  
Author(s):  
Md Mohiuddin ◽  
Asma Akther ◽  
Eun Byul Jo ◽  
Hyun Chan Kim ◽  
Jaehwan Kim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cellulose Acetate ◽  
Vibration Characteristics ◽  
Experimental Results ◽  
Vibration Velocity ◽  
Frequency Range ◽  
Actuation Frequency ◽  
Element Analysis ◽  
Wide Range

The present study investigates a film actuator made with dielectric cellulose acetate films separated by narrow spacers as a means of electrostatic actuation for potential haptic application. Fabrication process for the actuator is explained along with experiments conducted over a wide frequency range of actuation frequency. A valid finite element simulation of the actuator is made on the quarter section of the actuator by using full 3D finite elements. Vibration characteristics such as fundamental natural frequency, mode shape and output velocity in the frequency range for haptic feeling generation are obtained from the finite element analysis and compared with the experimental results. Experimental results demonstrate that the finite element model is practical and effective enough in predicting the vibration characteristics of the actuator for haptic application. The film actuator shows many promising properties like high transparency, wide range of actuation frequency and high vibration velocity for instance.

scholarly journals Development of New Baseball Pitching Machine with Four-Roller Throwing Mechanism

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 8
Author(s):  
Shinobu Sakai ◽  
Jin-Xing Shi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rotational Speed ◽  
Spin Axis ◽  
Element Analysis ◽  
Wide Range

At present, there are only a few developed pitching machines that can throw a ball with gyro spin. In this study, we aimed to develop a new baseball pitching machine using four rollers, where the rotational speed of each of the four rollers and the crossing angle of the opposite gyro rollers can be controlled optionally to generate an objective gyro spin more efficiently. We also elucidate the throwing mechanism of the developed baseball pitching machine and confirm its performance by finite element analysis. The newly developed pitching machine can throw a baseball with a wide range of speeds from 22.2 m/s (80 km/h) to 44.4 m/s (160 km/h) with all pitch types (fastball, curveball, gyroball, etc.), and the spin axis can be controlled in any designated direction. Moreover, this machine is capable of throwing a baseball with higher accuracy compared to commercially available pitching machines.

Effects of Ultrasonic Motor Stator Teeth Height on Start Reliability

2015 ◽  
Vol 0 (0) ◽  
Author(s):  
Wei Zheng ◽  
Jing-Liang Zhou ◽  
Yu-Zhen Ruan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Traveling Wave ◽  
Ultrasonic Motor ◽  
Wave Type ◽  
Element Analysis ◽  
Factors Affecting ◽  
Ultrasonic Motors ◽  
Wide Range ◽  
New Type

AbstractAs a new type of motor, the traveling wave type rotary ultrasonic motors (TRUM) have a wide range of applications. However, the friction between stator and rotor leads to its poor start reliability, which retards the progress of application of ultrasonic motors. Sometimes TRUMs which are widely used cannot start after storage. Height of tooth of the ultrasonic motor’s stator is one of the factors affecting TRUM’s start stabilizing. In this paper, combined with the ultrasonic motor running mechanism, the factors that affect TRUM’s start reliability are studied. Model of ultrasonic motor stator tooth height is analyzed by finite element analysis (FEA). Five TRUMs with different tooth heights are fabricated and measured. A TRUM with 1.85 mm tooth height can start properly in humidity 90%, but ultrasonic motors with 1.8–1.9 mm tooth height cannot start properly under the same conditions.

scholarly journals Multistage Tool Path Optimisation of Single-Point Incremental Forming Process

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6794
Author(s):  
Zhou Yan ◽  
Hany Hassanin ◽  
Mahmoud Ahmed El-Sayed ◽  
Hossam Mohamed Eldessouky ◽  
Joy Rizki Pangestu Djuansjah ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Processing Time ◽  
Incremental Forming ◽  
Single Point ◽  
Computational Time ◽  
Single Point Incremental Forming ◽  
Two Stage ◽  
Element Analysis ◽  
Wide Range

Single-point incremental forming (SPIF) is a flexible technology that can form a wide range of sheet metal products without the need for using punch and die sets. As a relatively cheap and die-less process, this technology is preferable for small and medium customised production. However, the SPIF technology has drawbacks, such as the geometrical inaccuracy and the thickness uniformity of the shaped part. This research aims to optimise the formed part geometric accuracy and reduce the processing time of a two-stage forming strategy of SPIF. Finite element analysis (FEA) was initially used and validated using experimental literature data. Furthermore, the design of experiments (DoE) statistical approach was used to optimise the proposed two-stage SPIF technique. The mass scaling technique was applied during the finite element analysis to minimise the computational time. The results showed that the step size during forming stage two significantly affected the geometrical accuracy of the part, whereas the forming depth during stage one was insignificant to the part quality. It was also revealed that the geometrical improvement had taken place along the base and the wall regions. However, the areas near the clamp system showed minor improvements. The optimised two-stage strategy successfully decreased both the geometrical inaccuracy and processing time. After optimisation, the average values of the geometrical deviation and forming time were reduced by 25% and 55.56%, respectively.

Application of subloading-overstress friction model to finite element analysis

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
T. Kuwayama ◽  
K. Hashiguchi ◽  
N. Suzuki ◽  
N. Yoshinaga ◽  
S. Ogawa
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Flat Surface ◽  
Surface Friction ◽  
Friction Model ◽  
Sliding Velocity ◽  
Element Analysis ◽  
Contact Behaviour ◽  
Wide Range ◽  
The Finite Element Analysis

Accurate prediction of contact behaviour between machine tools and metals is required for the mechanical design of machinery. In this article, the numerical analysis of the contact behaviour is described by incorporating the subloading-overstress model [6] which is capable of describing the contact behaviour for a wide range of sliding velocity including the increase of coefficient of friction with the increase of sliding velocity. And its validity is verified by the comparison with some test results. First, in order to examine the influence of sliding velocities on the friction properties, the flat-surface friction tests for lubricated interfaces between galvannealed steel sheet and SKD-11 tool steel were performed. As a result, It is observed that the friction smoothly translate to kinetic friction, after exhibiting the peak at the static friction. In addition, it is observed that the higher the sliding velocity, the larger the friction resistance, meaning the positive rate sensitivity. Then the subloading-overstress model is implemented in the finite element analysis program ABAQUS/Standard, and it is used to simulate the flat-surface friction tests. The predictions from the finite element analysis are shown to be in very good agreement with experimental results.

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