Estimation of Grasp Envelope Using a 3-Dimensional Kinematic Model of the Hand

2007 ◽  
Vol 51 (15) ◽  
pp. 889-893 ◽  
Author(s):  
Jaewon Choi ◽  
D. Christian Grieshaber ◽  
Thomas J. Armstrong
Keyword(s):  
Kinematic Model ◽  
Experimental Studies ◽  
Design Stage ◽  
Contact Algorithm ◽  
3 Dimensional ◽  
Rotation Method ◽  
Simulation Results ◽  
Practical Information ◽  
Object Shapes ◽  
Simple Contact

A 3-dimensional kinematic model of the hand was developed. The model predicts hand posture using a simple contact algorithm, which detects a contact between hand segments and the object. Using the 3-dimensional kinematic model of the hand, we estimated grasp envelopes because the space requirement for a specific task is an important aspect to be considered in the task's design stage. For this purpose, two hose insertion methods – a straight method and a rotation method – were simulated. The simulation results were compared favorably with the experimental studies by the previous researches. The model can be used to estimate grasp envelopes for varying hand sizes, object sizes, object shapes, and grip types. The model gives useful and practical information about the grasp envelope to the engineers who design parts or work space.

scholarly journals Full-Field Viscoelastic Inflation Response of Bovine Cornea

2008 ◽  
Author(s):  
B. L. Boyce ◽  
T. D. Nguyen ◽  
R. E. Jones
Keyword(s):  
Real Time ◽  
Experimental Studies ◽  
Time Dependent ◽  
Full Field ◽  
3 Dimensional ◽  
Displacement Mapping ◽  
Mapping Tool ◽  
Unique Approach ◽  
In Vivo Characterization

Most previous experimental studies and mechanical cornea models have ignored time-dependence of the cornea’s modulus, with only a few notable exceptions [1–3]. The purpose of the present work was to evaluate the time-dependent properties of cornea tissue independent of scleral contributions in a condition that is as physiologically-relevant as possible without resorting to costly and difficult in vivo characterization. A non-contact 3-dimensional displacement mapping tool was employed to image the entire deformation field across the entire cornea in real-time during pressurization. Unlike prior inflation-based studies, the present study’s unique approach permits dynamic real-time full-field mapping of deformation during inflation for the examination of viscoelasticity, isotropy, and homogeneity.

Simulation of a Hydropneumatic Suspension for Agricultural Working Vehicles

2021 ◽  
pp. 268-287
Author(s):  
Nicola Bosso ◽  
Nicolò Zampieri ◽  
Aurelio Somà ◽  
Francesco Mocera ◽  
Emanuele Conte
Keyword(s):  
Kinematic Model ◽  
Suspension System ◽  
Vehicle Performance ◽  
Vehicle Simulation ◽  
Complete Vehicle ◽  
Simulation Results

The chapter shows the study and simulation of a hydropneumatic suspension to be adopted for a telescopic handler vehicle. The hydropneumatic suspension system with independent wheels and with quadrilateral architecture has been studied to improve comfort and productivity of the existing vehicle, which has a suspended rigid axle on the front and a rigid axle on the rear, limiting the comfort and the grip. After the choice of the architecture and the kind of suspension, the chapter shows the design of the suspension kinematics. The optimization of the characteristic angles of the suspension has been performed using Adams/Car and Adams/Insight. The kinematic model optimized is subsequently reproduced in Adams/View to simulate the dynamics of the complete vehicle. Simulation results are used to evaluate vehicle performance in terms of comfort and stability according to the methods proposed by the standards.

scholarly journals Damage progression from impact in layered glass modeled with peridynamics

2012 ◽  
Vol 2 (4) ◽  
Author(s):  
Florin Bobaru ◽  
Youn Ha ◽  
Wenke Hu
Keyword(s):  
Spatial Resolution ◽  
Damage Evolution ◽  
Dynamic Interaction ◽  
Stress Waves ◽  
Three Dimensions ◽  
Contact Conditions ◽  
Peridynamic Model ◽  
Simulation Results ◽  
Simple Contact ◽  
Computational Resources

AbstractDynamic fracture in brittle materials has been difficult to model and predict. Interfaces, such as those present in multi-layered glass systems, further complicate this problem. In this paper we use a simplified peridynamic model of a multi-layer glass system to simulate damage evolution under impact with a high-velocity projectile. The simulation results are compared with results from recently published experiments. Many of the damage morphologies reported in the experiments are captured by the peridynamic results. Some finer details seen in experiments and not replicated by the computational model due to limitations in available computational resources that limited the spatial resolution of the model, and to the simple contact conditions between the layers instead of the polyurethane bonding used in the experiments. The peridynamic model uncovers a fascinating time-evolution of damage and the dynamic interaction between the stress waves, propagating cracks, interfaces, and bending deformations, in three-dimensions.

scholarly journals Analytical Calculation for Capacitances of Electrode Patterns in Touch Panels

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Bau-Jy Liang ◽  
Don-Gey Liu ◽  
Chia-Hung Yeh ◽  
Hsiao-Chun Chen ◽  
Yu-Chen Fang ◽  
...  
Keyword(s):  
Analytical Solution ◽  
Closed Form ◽  
Analytical Method ◽  
Analytical Calculation ◽  
3 Dimensional ◽  
Simulation Results ◽  
Complex Patterns ◽  
Touch Panels

AbstractIn this paper, an accurate 3-dimensional (3-D) analytical solution is proposed to calculate the projective capacitances of touch panels. In this study, both simple and complex patterns were investigated for the calculation. We propose a partition strategy to divide a pattern into many rectangular or triangular sub-patterns. Each sub-pattern can be further cut into 2-D slices. The capacitance of a 2-D slice was then solved by our closed-form formulae. The total capacitance of a pattern was obtained by integrating up all the partial capacitances of the slices. In this study, the precision of our analytical method was examined by comparing the simulation results obtained from Q3D

Simple Contact Stiffness Model Validation for Tie Bolt Rotor Design With Butt Joints and Pilot Fits

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Aaron M. Rimpel ◽  
Matthew Leopard
Keyword(s):  
Natural Frequencies ◽  
Contact Stiffness ◽  
Butt Joint ◽  
Design Stage ◽  
Design Calculation ◽  
Butt Joints ◽  
Modeling Approach ◽  
Stiffness Model ◽  
Joint Location ◽  
Simple Contact

Abstract Tie bolt rotors for centrifugal compressors comprise multiple shaft components that are held together by a single tie bolt. The axial connections of these rotors—including butt joints, Hirth couplings, and Curvic couplings—exhibit a contact stiffness effect, which tends to lower the shaft bending frequencies compared to geometrically identical monolithic shafts. If not accounted for in the design stage, shaft bending critical speed margins can be compromised after a rotor is built. A previous paper had investigated the effect of tie bolt force on the bending stiffness of stacked rotor assemblies with butt joint interfaces, both with and without pilot fits. This previous work derived an empirical contact stiffness model and developed a practical finite element modeling approach for simulating the axial contact surfaces, which was validated by predicting natural frequencies for several test rotor configurations. The present work built on these previous results by implementing the same contact stiffness modeling approach on a real tie bolt rotor system designed for a high pressure centrifugal compressor application. Each joint location included two axial contact faces, with contact pressures up to five times higher than previously modeled, and a locating pilot fit. The free-free natural frequencies for different amounts of tie bolt preload force were measured, and the frequencies exhibited the expected stiffening behavior with increasing preload. However, a discontinuity in the data trend indicated a step-change increase in the contact stiffness. It was shown that this was likely due to one or more of the contact faces becoming fully engaged only after sufficient tie bolt force was applied. Finally, a design calculation was presented that can be used to estimate whether contact stiffness effects may be ignored, which could simplify rotor analyses if adequate contact pressure is used.

Numerical Co-Simulation of Drag Torque in the Gearbox Combined Multibody Dynamics With Moving Particle Semi-Implicit Method

2019 ◽  
Author(s):  
Lifu Zhang ◽  
Guangqiang Wu ◽  
Lijuan Ju
Keyword(s):  
Power Loss ◽  
Friction Pair ◽  
Helical Gear ◽  
Implicit Method ◽  
Design Stage ◽  
Force Transmission ◽  
Technical Measure ◽  
New Approach ◽  
Simulation Results ◽  
Moving Particle

Abstract In the gearbox, lubrication is an important technical measure to improve the friction state of the friction pair and ensure the smooth operation of the mechanical system, and it also plays an important role in cooling, sealing, rust prevention, shock absorption and force transmission. Common lubrication methods in automobile gearbox include dip lubrication, splash lubrication and forced lubrication, but dip and splash lubrication often result in oil churning power loss of the gearbox, and predicting this loss at design stage can help designers to modify the design and improve efficiency. In this paper, the moving particle semi-implicit method is applied to analyze the churning loss of a single helical gear in the transmission system, and the accuracy of the simulation results is verified by experimental data. This research can provide an effective new approach to study the oil churning power loss of gear in transmission.

Simple Contact Stiffness Model Validation for Tie Bolt Rotor Design With Butt Joints and Pilot Fits

2019 ◽  
Author(s):  
Aaron M. Rimpel ◽  
Matthew Leopard
Keyword(s):  
Natural Frequencies ◽  
Contact Stiffness ◽  
Butt Joint ◽  
Design Stage ◽  
Design Calculation ◽  
Butt Joints ◽  
Modeling Approach ◽  
Stiffness Model ◽  
Joint Location ◽  
Simple Contact

Abstract Tie bolt rotors for centrifugal compressors comprise multiple shaft components that are held together by a single tie bolt. The axial connections of these rotors — including butt joints, Hirth couplings, and Curvic couplings — exhibit a contact stiffness effect, which tends to lower the shaft bending frequencies compared to geometrically identical monolithic shafts. If not accounted for in the design stage, shaft bending critical speed margins can be compromised after a rotor is built. A previous paper had investigated the effect of tie bolt force on the bending stiffness of stacked rotor assemblies with butt joint interfaces, both with and without pilot fits. This previous work derived an empirical contact stiffness model and developed a practical finite element modeling approach for simulating the axial contact surfaces, which was validated by predicting natural frequencies for several test rotor configurations. The present work built on these previous results by implementing the same contact stiffness modeling approach on a real tie bolt rotor system designed for a high pressure centrifugal compressor application. Each joint location included two axial contact faces, with contact pressures up to five times higher than previously modeled, and a locating pilot fit. The free-free natural frequencies for different amounts of tie bolt preload force were measured, and the frequencies exhibited the expected stiffening behavior with increasing preload. However, a discontinuity in the data trend indicated a step-change increase in the contact stiffness. It was shown that this was likely due to one or more of the contact faces becoming fully engaged only after sufficient tie bolt force was applied. Finally, a design calculation was presented that can be used to estimate whether contact stiffness effects may be ignored, which could simplify rotor analyses if adequate contact pressure is used.

Thermal-Hydraulic Simulations of Guard Containment in Depressurization Accidents of a Gas-Cooled Fast Reactor

2013 ◽  
Author(s):  
Zhanjie Xu ◽  
Thomas Jordan
Keyword(s):  
Fast Reactor ◽  
Nuclear Reactor ◽  
Source Term ◽  
Reference Value ◽  
Design Stage ◽  
Primary System ◽  
Simulation Results ◽  
Accident Scenarios ◽  
Design Pressure ◽  
The Eu

A gas-cooled fast reactor is designed as an advanced nuclear reactor in next generation in the EU. In depressurization accident scenarios, pressurization caused by a release of helium from the primary system with a higher pressure into the guard containment would endanger the integrity of the containment. In the design stage, the released source term is analyzed theoretically, and is applied as a boundary condition in the 3D CFD code simulation to the transient pressurization process. The simulation results supply a reference value about the design pressure of the containment.

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