scholarly journals Dynamics of glass windows in mining vehicles under the impacts of rock pieces: numerical and analytical comparison for computational models validation

2021 ◽  
Vol 942 (1) ◽  
pp. 012009
Author(s):  
O Sukhanova ◽  
O Larin ◽  
B Ziętek
Keyword(s):  
Computational Models ◽  
Numerical Solutions ◽  
Underground Mining ◽  
Mesh Size ◽  
Work Conditions ◽  
Dynamics Analysis ◽  
Linear Dynamics ◽  
Safety Work ◽  
Models Validation ◽  
Mining Vehicles

Abstract This study represents the results of linear dynamics analysis of glass plates subjected to rock pieces impacts occurring in underground machines’ windows. The aim of the work is to provide analytical and numerical solutions, obtain frequencies and plate displacement, and compare results of stress calculation for different models. The work performs finite element method (FEM) computations within a modal analysis in 3D statement including a mesh-size convergence analysis. Given approach is a basement for estimation of safety work conditions for operators in cabins of underground mining vehicles when glass windows are subjected to rock bursts and damages.

Analytical Study of a Piezoelectric Frequency Up-Conversion Harvester Under Sawtooth Wave Excitation

2018 ◽  
Author(s):  
Saeed Onsorynezhad ◽  
Amin Abedini ◽  
Fengxia Wang
Keyword(s):  
Numerical Solutions ◽  
Excitation Frequency ◽  
Dynamics Analysis ◽  
Periodic Motions ◽  
Lumped Model ◽  
Sawtooth Wave ◽  
Piezoelectric Beam ◽  
Period 2 ◽  
Mass Spring ◽  
The Impact

In this work, an impact based frequency up-conversion mechanism is studied via discontinuous dynamics analysis. The mechanism consists of a moving stopper and a piezoelectric beam. The repeated free vibration of the piezoelectric beam achieved through the impaction between the stopper and the beam, With the stopper excited by a sawtooth wave. Due to the impact, the system contains complex discontinuous dynamics, hence to better understand the energy harvesting performance of the piezoelectric beam, we seek the simple periodic motions of the system. As the system parameter varies, the output voltage and power of the piezoelectric beam with periodic motions is obtained. These results were also compared with those obtained when the piezoelectric beam is directly subjected to the same sawtooth wave. The piezoelectric beam was modeled as a mass-spring-damper system, and the linear piezoelectric constitutive equations have been used to obtain the lumped model of the piezoelectric beam. In this study, numerical solutions of the generated power and voltage were obtained via discontinuous dynamics analysis. When the excitation frequency is low, the effect of frequency-up-conversion is demonstrated by comparing the generated power of two cases: piezoelectric beam excited via impact and beam directly subject to the sawtooth wave. The stable and unstable periodic motions and bifurcation trees of the impact parameters are predicted analytically versus varying excitation frequency for period-1 and period-2.

What localizes beneath: A metric multisensor localization and mapping system for autonomous underground mining vehicles

2020 ◽  
Vol 38 (1) ◽  
pp. 5-27 ◽  
Author(s):  
Adam Jacobson ◽  
Fan Zeng ◽  
David Smith ◽  
Nigel Boswell ◽  
Thierry Peynot ◽  
...  
Keyword(s):  
Underground Mining ◽  
Localization And Mapping ◽  
Mapping System ◽  
Mining Vehicles

Effects of Linear Hysteric Material Damping and Shock Pulse Shapes for Uniform Board Response

2016 ◽  
Author(s):  
Sharan Kallolimath ◽  
Jiang Zhou
Keyword(s):  
Test Performance ◽  
Strain Distribution ◽  
Computational Models ◽  
Numerical Solutions ◽  
Flexural Rigidity ◽  
Interpolation Method ◽  
Computational Time ◽  
Stress Concentrations ◽  
Stress Strain ◽  
Test Board

Validation of surface mounted electronic devices for drop test performance is considered as one of the most challenging tasks for researchers to search for key dynamic parameters either by experimentation or by numerical simulation. It has not only become challenging task to capture some of the important parameters that affect board flexural rigidity, stiffness, dynamic stresses and strains, but also avoid stress concentrations near undesired locations resulting in non-uniform strain distribution throughout the test board. There is a requirement to simulate exact drop condition that quantifies high impact energy on the board and also control drop to improve the board surface stress/strain distribution measured should be independent from standoff stress region. In this paper, an effort to find the importance of viscous and linear hysteric damping characteristics on uniform board response has been made. The influence of damped responses during no ring impact has been analyzed. Two different types of computational models are developed and an approximate FEA numerical solutions are obtained to compare current JEDEC test board and alternative hexagonal boards at reduced computational time and challenging experimental cost. The effect of board responses with two types of linear damping models are considered to study the effect. An approach towards finding key parameters that affect stress/strain distribution under both free as well as constrained model has been made, with including different pulse shapes parameters into effect. Maximum board strains are validated and compared using Global FEA model and maximum stresses on the components are evaluated using cut boundary interpolation method. Comparative to empirical results data, an effort to improve uniform stress strain distribution of package solder joints has been made and results are correlated.

scholarly journals Analyzing Accidents in Civil Construction for Safety Work at Height

2019 ◽  
Vol 7 (11) ◽  
pp. 231-242
Author(s):  
Daniel Da Silva Damasceno ◽  
Josiane De Oliveira Martins ◽  
Frank Henrique Santos Fontineles ◽  
Sara Dos Santos Santarém ◽  
David Barbosa de Alencar ◽  
...  
Keyword(s):  
Construction Industry ◽  
Work Conditions ◽  
Lower Limbs ◽  
Construction Site ◽  
Safety Devices ◽  
Physical Integrity ◽  
Safety Work ◽  
Risk Of Falls ◽  
Single Use ◽  
The Rich

In civil construction any and all services must be performed objectively and safely, especially the services at the height of the painter, where the employee is more exposed to the risk of falls and impacts of the user's own objects on lower limbs. Both the employee and the employer are responsible for everything that happens at the construction site, the employer providing safety devices and plans to minimize the rich of accidents while performing the services and the employee must obey any and all safety orders and plans aimed at not only your physical integrity but that of your colleagues doing services around you. Therefore this work will address the NR-6 regulations dealing with single use equipment, NR-18 which work conditions and environment in the construction industry and NR-35 work at height, which regulate service at height with the main focus.

scholarly journals A Computational Model for Drug Release from PLGA Implant

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2416 ◽  
Author(s):  
Miljan Milosevic ◽  
Dusica Stojanovic ◽  
Vladimir Simic ◽  
Bogdan Milicevic ◽  
Andjela Radisavljevic ◽  
...  
Keyword(s):  
Finite Elements ◽  
Drug Release ◽  
Computational Models ◽  
Numerical Solutions ◽  
Surrounding Medium ◽  
Three Dimensional ◽  
Fiber Network ◽  
System A ◽  
Nanofiber Mats ◽  
Diffusion Mass

Due to the relative ease of producing nanofibers with a core–shell structure, emulsion electrospinning has been investigated intensively in making nanofibrous drug delivery systems for controlled and sustained release. Predictions of drug release rates from the poly (d,l-lactic-co-glycolic acid) (PLGA) produced via emulsion electrospinning can be a very difficult task due to the complexity of the system. A computational finite element methodology was used to calculate the diffusion mass transport of Rhodamine B (fluorescent drug model). Degradation effects and hydrophobicity (partitioning phenomenon) at the fiber/surrounding interface were included in the models. The results are validated by experiments where electrospun PLGA nanofiber mats with different contents were used. A new approach to three-dimensional (3D) modeling of nanofibers is presented in this work. The authors have introduced two original models for diffusive drug release from nanofibers to the 3D surrounding medium discretized by continuum 3D finite elements: (1) A model with simple radial one-dimensional (1D) finite elements, and (2) a model consisting of composite smeared finite elements (CSFEs). Numerical solutions, compared to experiments, demonstrate that both computational models provide accurate predictions of the diffusion process and can therefore serve as efficient tools for describing transport inside a polymer fiber network and drug release to the surrounding porous medium.

Reactive navigation and opportunistic localization for autonomous underground mining vehicles

2002 ◽  
Vol 145 (1-2) ◽  
pp. 127-146 ◽  
Author(s):  
Jonathan M Roberts ◽  
Elliot S Duff ◽  
Peter I Corke
Keyword(s):  
Underground Mining ◽  
Reactive Navigation ◽  
Mining Vehicles

Numerical Simulation of Pre- and Postsurgical Flow in a Giant Basilar Aneurysm

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Vitaliy L. Rayz ◽  
Michael T. Lawton ◽  
Alastair J. Martin ◽  
William L. Young ◽  
David Saloner
Keyword(s):  
Numerical Simulation ◽  
Vertebral Artery ◽  
Computational Models ◽  
Numerical Solutions ◽  
Cerebral Aneurysms ◽  
Flow Region ◽  
Secondary Flows ◽  
Patient Specific ◽  
Interventional Treatment ◽  
Slow Flow

Computational modeling of the flow in cerebral aneurysms is an evolving technique that may play an important role in surgical planning. In this study, we simulated the flow in a giant basilar aneurysm before and after surgical takedown of one vertebral artery. Patient-specific geometry and flowrates obtained from magnetic resonance (MR) angiography and velocimetry were used to simulate the flow prior to and after the surgery. Numerical solutions for steady and pulsatile flows were obtained. Highly three-dimensional flows, with strong secondary flows, were computed in the aneurysm in the presurgical and postsurgical conditions. The computational results predicted that occlusion of a vertebral artery would result in a significant increase of the slow flow region formed in the bulge of the aneurysm, where increased particle residence time and velocities lower than 2.5cm∕s were computed. The region of slow flow was found to have filled with thrombus following surgery. Predictions of numerical simulation methods are consistent with the observed outcome following surgical treatment of an aneurysm. The study demonstrates that computational models may provide hypotheses to test in future studies, and might offer guidance for the interventional treatment of cerebral aneurysms.

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