scholarly journals Engineering our Favorite Pastime

2010 ◽  
Vol 132 (04) ◽  
pp. 44-48
Author(s):  
Lloyd Smith ◽  
James Sherwood
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Layer By Layer ◽  
Ball Impact ◽  
Support Mechanism ◽  
Bat Performance ◽  
Technology Advances

This article describes the equipment and technology advances in baseball and softball games. Research efforts are currently being pursued by the authors to develop a layer-by-layer finite element model of a baseball. While work on improved ball models is ongoing, a number of significant accomplishments have been made with current models. These include comparing bat performance, describing the plastic deformation (denting) observed in metal bats, and the failure modes observed with wood bats. To simulate the bat/ball impact at game-like speeds, a durability machine is used to fire balls at a bat at speeds up to 200 mph, at the rate of 10 per minute. After a ball is shot, it falls into a trough and is loaded back into the magazine, which holds up to 36 balls. The bat-support mechanism simulates the grip and flexibility of a batter and can be programmed to rotate the bat between hits to simulate the use of hollow bats or to remain “label up” as is needed for wood bats.

Research on seismic behavior of special-shaped CFST column to H-section steel beam joint

2021 ◽  
pp. 136943322110073
Author(s):  
Yu Cheng ◽  
Yuanlong Yang ◽  
Binyang Li ◽  
Jiepeng Liu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Behavior ◽  
Failure Modes ◽  
Joint Stiffness ◽  
Load Ratio ◽  
Element Model ◽  
Steel Tube ◽  
Steel Beam ◽  
Static Test

To investigate the seismic behavior of joint between special-shaped concrete-filled steel tubular (CFST) column and H-section steel beam, a pseudo-static test was carried out on five specimens with scale ratio of 1:2. The investigated factors include stiffening types of steel tube (multi-cell and tensile bar) and connection types (exterior diaphragm and vertical rib). The failure modes, hysteresis curves, skeleton curves, stress distribution, and joint shear deformation of specimens were analyzed to investigate the seismic behaviors of joints. The test results showed the connections of exterior diaphragm and vertical rib have good seismic behavior and can be identified as rigid joint in the frames with bracing system according to Eurocode 3. The joint of special-shaped column with tensile bars have better seismic performance by using through vertical rib connection. Furthermore, a finite element model was established and a parametric analysis with the finite element model was conducted to investigate the influences of following parameters on the joint stiffness: width-to-thickness ratio of column steel tube, beam-to-column linear stiffness ratio, vertical rib dimensions, and axial load ratio of column. Lastly, preliminary design suggestions were proposed.

Thermo-Mechanical Analysis of Instrumentation Guide Tube Failure During a Severe Accident in a Nordic Boiling Water Reactor

2020 ◽  
Author(s):  
Ying Yue ◽  
Walter Villanueva ◽  
Hongdi Wang ◽  
Dingqu Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Boiling Water ◽  
Severe Accident ◽  
Boiling Water Reactor ◽  
Guide Tube ◽  
Water Reactor ◽  
Water Reactors

Abstract Vessel penetrations are important features of both pressurized water reactors and boiling water reactors. The thermal and structural behaviour of instrumentation guide tubes (IGTs) and control rod guide tubes (CRGTs) during a severe accident is vital in the assessment of the structure integrity of the reactor pressure vessel. Penetrations may fail due to welding failure, nozzle rupture, melt-through, etc. It is thus important to assess the failure mechanisms of penetrations with sufficient details. The objective of this paper is to assess the timing and failure modes of IGTs at the lower head during a severe accident in a Nordic boiling water reactor. In this study, a three-dimensional local finite element model was established using Ansys Mechanical that includes the vessel wall, the nozzle, and the weld joint. The thermo-mechanical loads of the finite element model were based on MELCOR results of a station blackout accident (SBO) combined with a large-break loss-of-coolant accident (LBLOCA) including an external vessel cooling by water as a severe accident management strategy. Given the temperature, creep strain, elastic strain, plastic strain, stress and displacement from the ANSYS simulations, the results showed the timing and failure modes of IGTs. Failure of the IGT penetration by nozzle creep is found to be the dominant failure mode of the vessel. However, it was also found that the IGT is clamped by the flow limiter before the nozzle creep, which means that IGT ejection is unlikely.

scholarly journals Combining Models to Simulate the Condition of the PVC Distribution Network

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 591
Author(s):  
Karel A. van Laarhoven ◽  
Bas A. Wols
Keyword(s):  
Finite Element ◽  
Drinking Water ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Angular Deflection ◽  
Soil Settlement ◽  
Overall Performance ◽  
Water Companies ◽  
Maintenance And Inspection

The failure of joints plays an important role in the overall performance of mains. One of the prevalent failure modes at polyvinyl chloride (PVC) joints is the rupture of pipe or joint, which may occur due to high angular deflection of the pipe with respect to the joint, caused by differential soil settlement. The present paper reports the construction and use of a finite element model to determine the maximum angular deflection of a variety of PVC joints in different loading situations. The resulting acceptable deflections vary between 3° and 8° per side, which differs significantly from installation guidelines. The results will support drinking water companies in substantiating the prioritization of maintenance and inspection.

A reaction-force-validated soccer ball finite element model

2016 ◽  
Vol 231 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Zahari Taha ◽  
Mohd Hasnun Arif Hassan
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Reaction Force ◽  
Element Model ◽  
Optimal Number ◽  
Ball Impact ◽  
Soccer Ball ◽  
Mesh Density ◽  
Good Agreement

The soccer ball is one of the important pieces of equipment in the game of soccer. It undergoes various forms of impact during the game. In order to numerically investigate the occasions of ball impact such as soccer heading, a validated finite element model of a soccer ball is required. Therefore, a model was developed incorporating material properties obtained from literature. To ensure the accuracy of the model, it was validated against an established soccer ball model and experimental data of the coefficient of restitution, contact time, longitudinal deformation and reaction force. In addition, a parametric study of the mesh density was also performed to determine the optimal number of elements. The developed soccer ball model was found to be in a good agreement with the literature and experimental data. This suggests that, the soccer ball model is capable of replicating the impacts of interest. This article details the development of the model and the validation processes.

A Finite Element Model for Spherical Debris Denting in Heavily Loaded Contacts

2004 ◽  
Vol 126 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Young Sup Kang ◽  
Farshid Sadeghi ◽  
Mike R. Hoeprich
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Friction Coefficient ◽  
Aspect Ratio ◽  
Finite Element Model ◽  
Contact Force ◽  
Material Properties ◽  
Element Model ◽  
Friction Coefficients ◽  
Elastic Plastic

The objective of this study is to develop models to investigate the effects of contaminants (debris denting process) in heavily loaded rolling and sliding contacts. A dynamic time dependent finite element model (FEM) was developed to determine the elastic-plastic deformation and contact force generated between the mating surfaces and a spherical debris as debris passes through the contact region. The FEA model was used to obtain the effects of various parameters such as debris sizes, material properties, friction coefficients, applied loads, and surface speeds on the elastic-plastic deformation and contact force of the system. The FEM was used to predict debris and mating surfaces deformations as a function of debris size, material properties, friction coefficient, applied load, and surface speed. Using the FEM, a parametric study demonstrated that material properties (i.e., modulus of elasticity, yield strength, ultimate strength and Poisson’s ratio) and friction coefficients play significant roles on the height and width of dents on the mating surfaces. For lower friction coefficients μd<0.3 the debris and mating surfaces slip more easily relative to one another and therefore the debris has lower aspect ratio. As friction coefficient is increased the debris and mating surfaces stick to one another and therefore the debris deforms less and has higher aspect ratio. The results indicate that the pressure generated between the debris and mating surfaces is high enough to plastically deform the debris and mating surfaces and cause a permanent dent on the surfaces and cause residual stresses around the dent. Based on the FEM results, a dry contact model (DCM) was developed to allow similar analyses as the FEM, however, in significantly shorter computational time.

Contribution of Surface Irregularities to Rolling Contact Plasticity in Bearing Steels

1995 ◽  
Vol 117 (4) ◽  
pp. 660-666 ◽  
Author(s):  
V. Gupta ◽  
G. T. Hahn ◽  
P. C. Bastias ◽  
C. A. Rubin
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Finite Element Model ◽  
Half Space ◽  
Kinematic Hardening ◽  
Constitutive Relations ◽  
Element Model ◽  
Bearing Steels ◽  
Deep Groove ◽  
Surface Irregularities

A “two-body” elasto-plastic finite element model of two-dimensional rolling and rolling-plus-sliding has been developed to treat the effect of surface irregularities. The model consists of a smooth cylinder in contact with a semi-infinite half-space that is either smooth or fitted with one of two irregularities: a 0.4 μm deep groove, or a 7 μm deep groove. The model incorporates elastic-linear-kinematic-hardening-plastic (ELKP) and nonlinear-kinematic-hardening-plastic (NLKP) material constitutive relations appropriate for hardened bearing steel and the 440C grade. The calculated contact pressure distribution is Hertzian for smooth body contact, and it displays intense, stationary, pressure spikes superposed on the Hertzian pressure for contact with the grooved and ridged surface. The results obtained for the 0.4 μm deep groove are consistent with those reported by Elsharkawy and Hamrock (1991) for an EHD lubricated contact. The effect of translating the counterface on the half space, as opposed to indenting the counterface on the half-space with no translation, is studied. The stress and strain values near the surface are found to be similar for the two cases, whereas they are significantly different in the subsurface. Efforts have been made to identify the material constitutive relations which best describe the deformation characteristics of the bearing steels in the initial few cycles. ELKP material constitutive relations produce less net plastic deformation in the initial stages, for a given stress, than seen in experiments. NLKP model produces more plasticity than the ELKP model and shows promise for treating the net distortions in the early stages. Artificial indents were inserted on the running track of the cylindrical rolling elements and profilometer measurements of these indents were made, before and after rolling. These preliminary measurements show that substantial plastic deformation takes place in the process of rolling. The deformations of the groove calculated with the finite element model are compared to those measured experimentally.

Simulating Responses of Buried Steel Pipe Crossing Reverse Fault

2011 ◽  
Vol 90-93 ◽  
pp. 825-828
Author(s):  
Lei Zhao ◽  
Jian Zhong Yang ◽  
Jin Xin Zhao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Local Buckling ◽  
Element Model ◽  
Pipe Diameter ◽  
Reverse Fault ◽  
Shell Finite Element ◽  
Dip Angle ◽  
The Finite Element Model

The responses of the buried pipeline due to reverse fault dislocating are studied by a 3-dimension shell finite element model with equivalent boundary spring in ANSYS program. The calculating length of the model is determined by dip angle of the reverse fault: The length is 150 times pipe diameter when the angle is equal to or bigger than 45°; but the length is 240 times pipe diameter when the angle is less than 45°. The finite element model is fit for computing that dip angle is less than 80°. Results show: Failure modes of the pipes are determined by dip angle and dislocation value of the fault. When the angle is gentle and the dislocation is small, either local buckling(wrinkling) or beam buckling can be happened. The angle is equal to or bigger than 75°, local buckling and beam buckling can be happened at same time.

scholarly journals A Double-Acting Piezoelectric Actuator for Helicopter Active Rotor

Actuators ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 247
Author(s):  
Jinlong Zhou ◽  
Linghua Dong ◽  
Weidong Yang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Piezoelectric Actuator ◽  
Performance Test ◽  
Failure Modes ◽  
Element Model ◽  
Test Results ◽  
Trailing Edge ◽  
Trailing Edge Flaps ◽  
Piezoelectric Stacks

An active rotor with trailing-edge flaps is an effective approach to alleviate vibrations and noise in helicopters. In this study, a compact piezoelectric actuator is proposed to drive trailing-edge flaps. The two groups of piezoelectric stacks accommodated in the actuator operate in opposition, and double-acting output can be realized through the differential motion of these stacks. A theoretical model and a finite element model are established to predict the output capability of this actuator, and structural optimization is performed using the finite element model. A prototype is built and tested on a benchtop to assess its performance. Test results demonstrate that the actuator stiffness reaches 801 N/mm, and its output stroke is up to ± 0.27 mm when subjected to actuation voltage of 120 V. Agreement between measurements and simulations validates the accuracy of the established models. In addition, actuator outputs in failure modes are measured by canceling the supply voltage of one group of piezoelectric stacks. In this condition, the actuator can still generate acceptable outputs, and the initial position of the output end remains unchanged. Simulations and test results reveal that the proposed actuator achieves promising performance, and it is capable to be applied to a helicopter active rotor.

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