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Author: Nicholas Papavizas
Publisher:
ISBN:
Category :
Languages : en
Pages :
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In this research, a three-degree-of-freedom (3-DOF) mathematical model is developed to predict the onset of unstable pitch/bounce-type vibrations in heavy, off-highway, mining haul trucks. This unstable vibration phenomenon can be described as an instance of power hop, a type of dynamic instability also seen in agricultural tractors, wheeled construction vehicles, and other off-highway vehicles (OHVs). A model that can adequately predict dynamic instability is a necessary first step in developing controls solutions that might be able to mitigate or even prevent unstable motion from occurring.The 3-DOF model describes a rear-wheel-drive (RWD) mining haul truck operating on a non-deformable, sloped surface. Analytical stability criteria are derived through closed-form eigenvalue analysis of the equations of motion while neglecting all damping terms. Numerical stability analysis studies parameter sensitivity for a representative haul truck with a 250 ton payload capacity in two payload scenarios: operation at empty vehicle weight (EVW) and operation at 100% payload capacity, or gross vehicle weight (GVW).Results show that the 3-DOF predicts dynamic instability. By utilizing a stability margin, the results further show that there are numerous different operating point configurations that could potentially lead to dynamic instability. Of the 33 million cases tested in each of the two different payload scenarios, 21% are deemed potentially unstable for the empty truck and 38% are deemed potentially unstable for the loaded truck. Furthermore, potentially unstable cases exist over the full range of parameters simulated. The analytical stability criteria derived from the undamped equations of motion do not always correlate with the numerical eigenvalue analysis of the full set of equations of motion that include all damping terms.Instability is shown to be heavily dependent on road grade, tire stiffness and damping properties, the location of the vehicles center of gravity, and forward travel speed. The model mainly predicts instability on severe road grades and at high speeds. A result not seen in previous studies of power hop in agricultural tractors is the prediction of dynamic instability when a vehicle travels downhill. While instability on uphill grades primarily occurs when the rear axle is stiffer than the front axle, the opposite is observed on downhill grades. Increased tire damping is shown to reduce the likelihood of instability in both loading scenarios and on all grades. Like tire stiffness, longitudinal center of gravity location also plays a role in whether the truck is more likely to become unstable on positive or negative road grades.
Author: Nicholas Papavizas
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
In this research, a three-degree-of-freedom (3-DOF) mathematical model is developed to predict the onset of unstable pitch/bounce-type vibrations in heavy, off-highway, mining haul trucks. This unstable vibration phenomenon can be described as an instance of power hop, a type of dynamic instability also seen in agricultural tractors, wheeled construction vehicles, and other off-highway vehicles (OHVs). A model that can adequately predict dynamic instability is a necessary first step in developing controls solutions that might be able to mitigate or even prevent unstable motion from occurring.The 3-DOF model describes a rear-wheel-drive (RWD) mining haul truck operating on a non-deformable, sloped surface. Analytical stability criteria are derived through closed-form eigenvalue analysis of the equations of motion while neglecting all damping terms. Numerical stability analysis studies parameter sensitivity for a representative haul truck with a 250 ton payload capacity in two payload scenarios: operation at empty vehicle weight (EVW) and operation at 100% payload capacity, or gross vehicle weight (GVW).Results show that the 3-DOF predicts dynamic instability. By utilizing a stability margin, the results further show that there are numerous different operating point configurations that could potentially lead to dynamic instability. Of the 33 million cases tested in each of the two different payload scenarios, 21% are deemed potentially unstable for the empty truck and 38% are deemed potentially unstable for the loaded truck. Furthermore, potentially unstable cases exist over the full range of parameters simulated. The analytical stability criteria derived from the undamped equations of motion do not always correlate with the numerical eigenvalue analysis of the full set of equations of motion that include all damping terms.Instability is shown to be heavily dependent on road grade, tire stiffness and damping properties, the location of the vehicles center of gravity, and forward travel speed. The model mainly predicts instability on severe road grades and at high speeds. A result not seen in previous studies of power hop in agricultural tractors is the prediction of dynamic instability when a vehicle travels downhill. While instability on uphill grades primarily occurs when the rear axle is stiffer than the front axle, the opposite is observed on downhill grades. Increased tire damping is shown to reduce the likelihood of instability in both loading scenarios and on all grades. Like tire stiffness, longitudinal center of gravity location also plays a role in whether the truck is more likely to become unstable on positive or negative road grades.
Author: Bruno Ayaga Kansake
Publisher:
ISBN:
Category :
Languages : en
Pages : 232
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Book Description
"Haul truck capacities have increased due to their economies of scale in large-scale surface mine production systems. Ultra-large trucks impose high dynamic loads on haul roads. The dynamic loads are exacerbated by road surface roughness and truck over-loading. The dynamic forces also subject trucks to high torsional stresses, which affect truck health. Current haul road response models are 2D and use static truckloads for low capacity trucks. Existing 3D models consider the road as a two-layer system. No models capture the truck dynamic effects on haul roads and predict strut pressures during haulage. Lagrangian mechanics was used to formulate the governing equations of the truck-haul road system. The equations were solved in MSC.ADAMS, based on multi-body dynamics, to generate the truck dynamic forces, which were verified and validated using data obtained from an open-pit mine. These forces were used in an FE model developed, verified and validated in ABAQUS to model the response of the haul road to the truck dynamic forces. The road was modeled using an elastoplastic Mohr-Coulomb model. The results showed that the maximum truck tire dynamic forces were 2.86 and 3.02 times the static force at rated payload and 20% over-loading, respectively. The trucks were exposed to torsional stresses that were up to 2.9 times the recommended threshold. Road deformation decreased with increasing layer modulus and increased with increasing payload. This study proposed novel multivariate models for predicting dynamic truck strut pressures. The novel 3D FE model and empirical relations for calculating truck dynamic forces incorporate truck dynamic forces into haul road design. This study forms a basis for designing structurally competent haul roads and improving truck health"--Abstract, page iii.
Author: Tad.S. Golosinski
Publisher: Routledge
ISBN: 1351427105
Category : Technology & Engineering
Languages : en
Pages : 280
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Book Description
First published in 1989. This volume includes papers of an International Symposium on "Off-Highway Haulage in Surface Mines" held in Edmonton, Canada, May 1989. They take up truck dispatch, fleet management, equipment, operations and safety, and haulroads.
Author: Duy Cuong Nguyen
Publisher: Springer Nature
ISBN: 3031222008
Category : Technology & Engineering
Languages : en
Pages : 1011
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Book Description
The International Conference on Engineering Research and Applications (ICERA 2022), held on December 1-2, 2022, at Thai Nguyen University of Technology in Thai Nguyen, Vietnam, provided an international forum to disseminate information on latest theories and practices in engineering research and applications. The conference focused on original research work in areas including mechanical engineering, materials and mechanics of materials, mechatronics and micro mechatronics, automotive engineering, electrical and electronics engineering, information and communication technology. By disseminating the latest advances in the field, the Proceedings of ICERA 2022, Advances in Engineering Research and Application, assists academics and professionals alike to reshape their thinking on sustainable development.
Author: Peter Darling
Publisher: SME
ISBN: 0873352645
Category : Technology & Engineering
Languages : en
Pages : 1912
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Book Description
This third edition of the SME Mining Engineering Handbook reaffirms its international reputation as "the handbook of choice" for today's practicing mining engineer. It distills the body of knowledge that characterizes mining engineering as a disciplinary field and has subsequently helped to inspire and inform generations of mining professionals.Virtually all of the information is original content, representing the latest information from more than 250 internationally recognized mining industry experts. Within the handbook's 115 thought-provoking chapters are current topics relevant to today's mining professional: Analyzing how the mining and minerals industry will develop over the medium and long term--why such changes are inevitable, what this will mean in terms of challenges, and how they could be managed Explaining the mechanics associated with the multifaceted world of mine and mineral economics, from the decisions associated with how best to finance a single piece of high-value equipment to the long-term cash-flow issues associated with mine planning at a mature operation Describing the recent and ongoing technical initiatives and engineering developments in relation to robotics, automation, acid rock drainage, block caving optimization, or process dewatering methods Examining in detail the methods and equipment available to achieve efficient, predictable, and safe rock breaking, whether employing a tunnel boring machine for development work, mineral extraction using a mobile miner, or cast blasting at a surface coal operation Identifying the salient points that dictate which is the safest, most efficient, and most versatile extraction method to employ, as well as describing in detail how each alternative is engineered Discussing the impacts that social and environmental issues have on mining from the pre-exploration phase to end-of-mine issues and beyond, and how to manage these two increasingly important factors to the benefit of both the mining companies and other stakeholders
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 772
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Author: Niousha Rahmani
Publisher:
ISBN:
Category : Mine haulage
Languages : en
Pages : 150
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Book Description
Mining methods have changed and grown to fulfill extractive demands. Heavy machinery is used to extract overburden in open pit and open cast mines and to create waste dumps prone to slope stability issues. As the heaviest equipment operating on dump locations, mine haul trucks require a safe, stable surface to work on, so the stability of waste dumps is hugely important. Slope failures frequently occur on mine cut slopes, embankments, dumps, and road cut surfaces, so an improved understanding, monitoring, and support of such slopes is important to prevent failure, loss of equipment and fatalities. One of the most important differences between waste dump slopes and other slopes such as embankments or road cuts is not only that waste dumps are made up of loose face dumped material but also goes that trucks impact cyclic loads which affect stability. For example, significant weight at hundreds of tonnes has a huge impact on slope stability. This cyclic loading scenario on mine waste dumps has yet to be investigated fully. This study looks at the stability of waste dumps under the impact of mining equipment based on physical modeling (laboratory scale tests), numerical modeling and "Slide" slope stability software. During the study on the stability of waste dumps by physical modeling, data related to rolling resistance was also recorded. It has been concluded that the results from both the physical and numerical modeling determined acceptable states for truck path by both truck location for the chosen test material, Dolomitic limestone (1/3 and 1/2 truck width from crest), and constructing a safety berm along the crest of slope, and for wet conditions.
Author: Danish Ali
Publisher:
ISBN:
Category : Damping (Mechanics)
Languages : en
Pages : 97
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Book Description
"The deployment of large capacity shovels and dump trucks, for achieving economic bulk production capacities, has resulted in high impact shovel loading operations (HISLO). These large shovels generate high impact forces when loading dump trucks with over 100-ton passes under gravity. The impact forces also generate high frequency shock waves, which cause severe truck vibrations, and thus, expose dump truck operators to high levels of whole body vibrations (WBV). The dynamic impact force generates these vibrations, and thus, there is a need to develop efficient technologies to eliminate or reduce its impact. Existing literature and industry practice show that this problem significantly impacts the health and safety of operators. There exists no fundamental work to address this problem. Thus, the primary objective of this research study is to provide scientific solutions to this problem. This research study develops a rigorous mathematical model to capture the dynamic impact force using all dependent underlying variables. A 3D virtual simulation model for a shovel dumping operation has also been developed using discrete element modeling (DEM) techniques in PFC3D. This model captures material dumping from a P&H 4100XPC shovel (100 tons per pass) into a CAT 793D truck. The results from the mathematical and simulation models showed good agreement. Analysis of the simulation results showed that a percent reduction of 4.88, 7.42, 11.45, 12.01, 15.08 and 17.34 % can be achieved by reducing the dumping height from 7.33 m to 6.33, 6.00, 5.50, 5.33, 5.00 and 4.9 m, respectively. The effect of the impulse force reductions on WBV exposures was examined using the model by Aouad and Frimpong (2013) in MSC ADAMS. Analysis of the results showed that for dumping height reductions to 7.33, 6.33, 6.00, 5.50, 5.33, 5.00 and 4.9 m, the RMS acceleration value of 3.56 m/s2 from Aouad and Frimpong (2013) can be reduced by 10.42, 15.51, 15.53, 15.73, 17.22, 18.85 and 19.61 %, respectively. This is equivalent to a reduction of 3.56 m/s2 to 2.86 m/s2 at a dumping height of 4.90 m. This research is a pioneering effort to address the problems associated with the operator exposures to severe WBV levels. It advances the heavy mining machinery vibrations frontier and contributes significantly to its body of knowledge. The mathematical and simulation models can be used to analyze any HISLO operation to reduce or possibly eliminate WBV exposures. This study ensures workplace safety and operator health under HISLO conditions in surface mining operations"--Abstract, page iii.
Author: Ernest K. Yanful
Publisher: Springer Science & Business Media
ISBN: 1402091397
Category : Technology & Engineering
Languages : en
Pages : 347
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Book Description
This book is the first edited compilation of selected, refereed papers submitted to ERTEP 2007. The selected papers either dealt with technologies or scientific work and policy findings that address specific environmental problems affecting humanity in general, but more specifically, people and ecosystems in developing countries. It was not necessary for the work to have been done in a developing country, but the findings and results must be appropriate or applicable to a developing country setting. It is acknowledged that environmental research, technology applications and policy implementation have been demonstrated to improve environmental sustainability and protection in several developed economies. The main argument of the book is that similar gains can be achieved in developing economies and economies in transition. The book is organized into six chapters along some of the key themes discussed at the conference: Environmental Health Management, Sustainable Energy and Fuel, Water Treatment, Purification and Protection, Mining and Environment, Soil Stabilization, and Environmental Monitoring. It is hoped that the contents of the book will provide an insight into some of the environmental and health mana- ment challenges confronting the developing world and the steps being taken to address them.
Author: Xu Kuangdi
Publisher: Springer Nature
ISBN: 9819920868
Category :
Languages : en
Pages : 2429
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