Analysis of Take-Off Performances for a Double-Joint Hopping Leg

2011 ◽  
Vol 211-212 ◽  
pp. 16-20
Author(s):  
Sheng Hai Hu ◽  
Kun Xiu Deng ◽  
Wei Fu ◽  
Lin Li
Keyword(s):  
Numerical Simulation ◽  
Energy Efficiency ◽  
Trajectory Planning ◽  
Center Of Mass ◽  
Kinematics And Dynamics ◽  
Simulation Approach ◽  
Hopping Robot ◽  
Relative Coordinates ◽  
Joint Trajectory Planning ◽  
The Impact

The paper is focused on a double-joint hopping leg driven by motors. Using relative coordinates, its kinematics and dynamics between the system and components are established during the launching stage of jumping, and the take-off mechanism is analyzed. Based on mechanics of jump movement and joint trajectory planning method, the impact of the change of the system initial posture and joint trajectories upon the system take-off performances, such as energy efficiency, instantaneous velocity of the system center of mass (CoM), is discussed by using numerical simulation approach with drive constraints. For a hopping robot, good take-off performances can improve its motion ability, so the resulted conclusions here provides a useful and helpful reference for analyzing and designing a multi-joint hopping robot.

scholarly journals Explicit dynamics based numerical simulation approach for assessment of impact of relief hole on blast induced deformation pattern in an underground face blast

2021 ◽  
Author(s):  
VIVEK HIMANSHU ◽  
A K Mishra ◽  
Ashish K Vishwakarma ◽  
M P Roy ◽  
P K Singh
Keyword(s):  
Numerical Simulation ◽  
Waveform Analysis ◽  
Deformation Pattern ◽  
Simulation Approach ◽  
Explicit Dynamics ◽  
Blasting Pattern ◽  
Development Face ◽  
Optimum Diameter ◽  
Relief Area ◽  
The Impact

Abstract The breakage of rock mass by blasting has many challenges. The optimal breakage in an underground development face/tunnel blast is dominantly dependent on the relief area provided to the blast holes. The cut portion in the burn cut face blast is significantly important to achieve the controlled deformation due to the blast. This paper has discussed the impact of the number and diameter of the relief holes on the breakage pattern of the rock. The numerical simulation with varying numbers and diameter of relief hole was carried out for this purpose. Finite element modeller explicit dynamics of Ansys-Autodyn was used for the simulation work. The isosurface of non-deformed zone was plotted to compare the extent of deformation under varying conditions of relief holes. The analysis shows that the higher number of relief holes with optimum diameter gives more controlled deformation than single relief hole with larger diameter. The nearfield vibration was also recorded by placement of seismograph. The waveform analysis of the recorded vibration was carried out. The redesigning of the blasting pattern was done using the results of numerical simulation and waveform analysis. The redesigned pattern consists of four relief holes of 115 mm diameter. The blasting output with the revised design has resulted into the considerable improvements in the pull and reduction of overbreak. The revised pattern has addressed the issue of the socket formation at the site.

scholarly journals Modelling on Shock-Induced Energy Release Behavior of Reactive Materials considering Mechanical-Thermal-Chemical Coupled Effect

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Baoyue Guo ◽  
Kerong Ren ◽  
Zhibin Li ◽  
Rong Chen
Keyword(s):  
Numerical Simulation ◽  
Energy Release ◽  
Simulation Approach ◽  
Release Behavior ◽  
Reactive Material ◽  
Reactive Materials ◽  
Coupled Effect ◽  
Macro Scale ◽  
The Military ◽  
The Impact

Reactive material (RM) is a new type of energetic material, which is widely used in the military technology fields such as fragmentation warheads and shaped charge warheads. Violent chemical reactions take place in the impact process of reactive materials, and how to realize the macro numerical simulation of shock-induced energy release behavior of reactive materials is one of the most urgent problems to be solved for its future military applications. In this study, a numerical simulation approach and procedure is proposed, which can simulate the shock-induced energy release behavior of reactive materials on a macro scale. Firstly, program implementation of the mechanical-thermal-chemical coupled effect model for RM is realized in the second-development interface of LS-DYNA software. Then, the adaptive simulated annealing algorithm is used to fit the chemical reaction kinetic parameters of RM using the direct ballistics test data. Finally, the simulation calculation of the fragment penetrating upon steel plate is carried out to expand the applicability of the numerical simulation approach proposed in this study. The results show that the numerical simulation approach proposed in this study can reproduce the results of the direct ballistics test more accurately, which assumes practical significance for the engineering application of reactive materials in the military field in the future.

Stochastic simulation for determining the design flood of cascade reservoir systems

2012 ◽  
Vol 43 (1-2) ◽  
pp. 54-63 ◽  
Author(s):  
Baohong Lu ◽  
Huanghe Gu ◽  
Ziyin Xie ◽  
Jiufu Liu ◽  
Lejun Ma ◽  
...  
Keyword(s):  
Simulation Model ◽  
Stochastic Simulation ◽  
Southern China ◽  
Flow Simulation ◽  
Simulation Method ◽  
Simulation Approach ◽  
Design Flood ◽  
Design Values ◽  
Stochastic Simulation Model ◽  
The Impact

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.

scholarly journals Impact of Passive Energy Efficiency Measures on Cooling Energy Demand in an Architectural Campus Building in Karachi, Pakistan

2021 ◽  
Vol 13 (13) ◽  
pp. 7251
Author(s):  
Mushk Bughio ◽  
Muhammad Shoaib Khan ◽  
Waqas Ahmed Mahar ◽  
Thorsten Schuetze
Keyword(s):  
Energy Efficiency ◽  
Energy Demand ◽  
Electricity Consumption ◽  
Information Modeling ◽  
Base Case ◽  
Energy Efficiency Measures ◽  
Efficiency Measures ◽  
The Impact ◽  
Cooling Energy Demand ◽  
Campus Building

Electric appliances for cooling and lighting are responsible for most of the increase in electricity consumption in Karachi, Pakistan. This study aims to investigate the impact of passive energy efficiency measures (PEEMs) on the potential reduction of indoor temperature and cooling energy demand of an architectural campus building (ACB) in Karachi, Pakistan. PEEMs focus on the building envelope’s design and construction, which is a key factor of influence on a building’s cooling energy demand. The existing architectural campus building was modeled using the building information modeling (BIM) software Autodesk Revit. Data related to the electricity consumption for cooling, building masses, occupancy conditions, utility bills, energy use intensity, as well as space types, were collected and analyzed to develop a virtual ACB model. The utility bill data were used to calibrate the DesignBuilder and EnergyPlus base case models of the existing ACB. The cooling energy demand was compared with different alternative building envelope compositions applied as PEEMs in the renovation of the existing exemplary ACB. Finally, cooling energy demand reduction potentials and the related potential electricity demand savings were determined. The quantification of the cooling energy demand facilitates the definition of the building’s electricity consumption benchmarks for cooling with specific technologies.

scholarly journals A review of challenges and benefits of integration of CHP plant into the grid: a case study in Serbia

2021 ◽  
Author(s):  
Rade M. Ciric ◽  
Sasa N. Mandic
Keyword(s):  
Energy Efficiency ◽  
Negative Impact ◽  
Renewable Energy Sources ◽  
Increase Energy Efficiency ◽  
High Voltage Supply ◽  
The Republic ◽  
Technical Solutions ◽  
The Impact

AbstractThe Republic of Serbia must make significant efforts to promote and exploit renewable energy sources and increase energy efficiency in all energy sectors to ensure energy security and economic competitiveness, reduce the negative impact on the environment from energy production and use, and contribute to global efforts to reduce greenhouse gases. Within the paper several issues of integration of recently realized CHP plant are introduced and discussed. Firstly, the legal and energy policy issues in the Republic of Serbia regarding connecting CHP to the grid are presented. The challenges and technical solutions for CHP connection to the grid, as well as power quality issues and the role of the CHP plant during the restoration of power supply during the maintenance of the substation and unplanned loss of high voltage supply, are presented and discussed. Finally, the impact of prospective massive integration of CHP on the energy balance and CO2 emission reduction in the province of Vojvodina in Serbia is investigated and discussed. Since it is the first CHP plant realized in Serbia, it is crucial that experience be shared to all potential stakeholders in the future energy efficiency projects.

scholarly journals Does a National Innovation System Encourage Sustainability? Lessons from the Construction Industry in Serbia

2021 ◽  
Vol 13 (7) ◽  
pp. 3591
Author(s):  
Marija Mosurović Ružičić ◽  
Mirjana Miletić ◽  
Marina Dobrota
Keyword(s):  
Energy Efficiency ◽  
Construction Industry ◽  
Innovation System ◽  
Business Environment ◽  
National Innovation System ◽  
Eastern European ◽  
System Perspective ◽  
Modern Business ◽  
Eastern European Countries ◽  
The Impact

Influences from the modern business environment indicate the need for the incorporation of sustainability concepts from an innovation system perspective. In the presented research, we emphasize the energy efficiency concept within the frame of sustainability and innovation. The aim of this research was to underline and explore the relationships between innovation, energy efficiency, and sustainability in the construction industry. To answer the research questions, a questionnaire was created to explore the impact of the energy efficiency certification process on the innovation behavior of construction industry enterprises in Serbia. The results show that energy efficiency has supported innovation, and that there exists a relationship between sustainability and innovativeness in the construction industry. Applying energy efficiency passports has influenced the co-operation of enterprises in the construction sector and other actors in the national innovation system in Serbia. The innovation concept demonstrates that enterprises in the construction industry should be observed as a part of the wider picture—the national innovation system. In turn, the specific context of a particular national innovation system should be seen within the wider picture of national innovation systems of Central and Eastern European Countries (CEECs).

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