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.
Efficient Spiral algorithm for Cutting Bit mapping on the Micro Trencher Blade
This paper presents a novel algorithm for placement of circular cutting bits on a 141.36 inch circular trencher blade for hard rock cutting to be able to lay fiber optic cable of varying width. The blade is divided into 6 x segments of 60 degree each. The spiral algorithm calculates the exact angle of hit, no. of bits and the angle of exposure to precisely cut the required width of hard rock patch for fiber optic cable lying. With the no. of bits and angle known the best cutting blade speed and speed of wheeled machine can be calculated to obtain précised outcome. Given the type of material to cut the algorithm can also estimate based on the above mentioned parameters the running cost of trenching blades/ km in terms of bits replacement to forecast the exact cost of trenching. The algorithm simulation on hard rock shows as the no. of bits are reduced on the circular trencher blade the bits replacement rate / km increases, the effect is even worse if simultaneously the bit ground penetrating angle is made wider. The effects are inversely proportional if the no. of bits is increased and the bit ground penetrating angle is made narrower. But there is a limit the n. of bits can be increased and the angle can be made narrower, beyond that limit the effect is not optimized. An already existing micro trencher by Ditch witch has been studied as a case study to compare the on ground performance and simulation performance. The test was conducted at CPEC route in Gilgit Pakistan. Keywords—Component, Trenching, cutting bits, circulat blade, rpm, speed, Micro trencher, Mean Time to Failure ( MTF).
Just Wars: From Cicero to Iraq
Preface and Acknowledgements. Introduction -. PART I: MAPPING THE JUST WAR TRADITION. Chapter 1: Antiquity -. Chapter 2: The Middle Ages -. Chapter 3: Renaissance and Reformation -. Chapter 4: From Holy War to Enlightenment -. Chapter 5: Modernity and Beyond -. PART II: CONTEMPORARY ISSUES. Chapter 6: The Just War Tradition Today -. Chapter 7: Terrorism -. Chapter 8: Pre-emption -. Chapter 9: Aerial Bombing -. Chapter 10: Humanitarian Intervention -. Conclusion. Bibliography -. Index