Parameter study of chain trenching machines of Underwater Construction Robots via analytical model
Analytical model by considering the kinematics, dynamics, and energetics of the trenching machine is adopted and proposed to design an underwater chain trenching machine at UCRC-KIOST. In this paper, parameter study and sensitivity analysis is conducted to show how the variations of operational and geometric parameters, as well as cutting tools and material condition affect the forces, moment, weight, and power components. The study sheds some important insights about how the trenching machine behaves and thus the information from this study can be used to design a trenching machine for the required working condition. The parameter study shows that minimum weight requirement for self-propelled vehicle is increased during operation at steep bar angle, and to keep the traction of the vehicle getting worst, it is recommended to cut the trench at low bar angle and make sure the cutting tool is still sharp. The results also show that traverse speed, cutting depth, uniaxial compressive strength, and trench width are the most sensitive parameters affecting the power and angular speed. On the other hand, weight of the vehicle, nose radius, bar length, and pivot point location does not affect the total chain power at all.
Mechanics of Cutting and Boring. Part 8: Dynamics and Energetics of Continuous Belt Machines,
Abstract : The report deals with forces and power requirements for cutting machines of the belt type, as exemplified by large chain saws and ladder trenchers. The forces of single cutting tools are considered, and related to the overall forces on a cutter bar. Forces are related to power, and sources of loss are identified. Tractive thrust and normal reaction are analyzed and used to assess the traction, weight and balance factors for self-propelled machines. Specific energy consumption and performance index are treated, and concepts of power density and apparent belt pressure are introduced. Requirements for acceleration of cuttings are assessed, and the report concludes with a set of worked examples. (Author)
Frequency selective surface design for blinds applications
In this paper, the reconfigurable blind structure with frequency selective surfaces(FSS) for the building applications are presented. Frequency transmission characteristics for different angles of the proposed blind-FSSs are investigated and verified through simulation and measurement. The simulation results show that we can implement the reconfigurable blind-FSS for multiband wireless applications. To verify the proposed paper, two kinds of blind-FSSs, crossed dipole FSS and circular ring FSS are fabricated and measurements are performed for different angles. The proposed structure in this paper which is very simple, can be easily applied to any planar surface for wireless security applications at low cost.