“…Besides, the superscript is used to distinguish different cylinder. The multi-fulcrum crankshaft is hyperstatic structure, and it is hard to solve the reaction forces for each fulcrum from equation (9). However, the reaction force can be extracted from the GEO-surface contact in the dynamic model.…”
Section: Force Analysismentioning
confidence: 99%
“…Pang et al 8 invented a shoulder joint exoskeleton rehabilitation mechanism with a fixed gear and a curved rack. Ahmed et al 9 analyzed the stress and stiffness of seven-teeth pinion and rack in offshore jack-up rig by finite element software. The study proved that the rack-pinion mechanism was still reliable under high load conditions.…”
Drilling pump is the heart of drilling rig, its core structure is crank-linkage mechanism. However, the drilling pump is criticized for its short stroke and high stroke frequency. Aiming at these defects, a long stroke reciprocating (LSR) pump combined the crank-linkage with a rack-pinion mechanism is proposed, and its dynamic and flow characteristics are researched. The results reveal that the stroke of the LSR pump is extended twice when the crank radius stays the same. The stroke frequency and flow pulsation rate are lowered under the same rated power. A new multi-fulcrum crankshaft is designed to extend its fatigue life, and the reaction forces of each fulcrum are solved by simulation. The influence of the fulcrums position on the crankshaft modal frequency is further investigated. The flexible characteristics of the multi-fulcrum crankshaft are studied by rigid-flexible coupled analysis. The results show that more fulcrums can effectively reduce the stress of crankshaft, and the maximum stress of the multi-fulcrum crankshaft is only 178.6 MPa. The modal frequency of the multi-fulcrum crankshaft is increased due to more fulcrums, which proved its stiffness and stability are improved. The fatigue life of the multi-fulcrum crankshaft is predicted to reach 30,000 h by finite element analysis. This study would provide a theoretical basis for further development of the LSR pump.
“…Besides, the superscript is used to distinguish different cylinder. The multi-fulcrum crankshaft is hyperstatic structure, and it is hard to solve the reaction forces for each fulcrum from equation (9). However, the reaction force can be extracted from the GEO-surface contact in the dynamic model.…”
Section: Force Analysismentioning
confidence: 99%
“…Pang et al 8 invented a shoulder joint exoskeleton rehabilitation mechanism with a fixed gear and a curved rack. Ahmed et al 9 analyzed the stress and stiffness of seven-teeth pinion and rack in offshore jack-up rig by finite element software. The study proved that the rack-pinion mechanism was still reliable under high load conditions.…”
Drilling pump is the heart of drilling rig, its core structure is crank-linkage mechanism. However, the drilling pump is criticized for its short stroke and high stroke frequency. Aiming at these defects, a long stroke reciprocating (LSR) pump combined the crank-linkage with a rack-pinion mechanism is proposed, and its dynamic and flow characteristics are researched. The results reveal that the stroke of the LSR pump is extended twice when the crank radius stays the same. The stroke frequency and flow pulsation rate are lowered under the same rated power. A new multi-fulcrum crankshaft is designed to extend its fatigue life, and the reaction forces of each fulcrum are solved by simulation. The influence of the fulcrums position on the crankshaft modal frequency is further investigated. The flexible characteristics of the multi-fulcrum crankshaft are studied by rigid-flexible coupled analysis. The results show that more fulcrums can effectively reduce the stress of crankshaft, and the maximum stress of the multi-fulcrum crankshaft is only 178.6 MPa. The modal frequency of the multi-fulcrum crankshaft is increased due to more fulcrums, which proved its stiffness and stability are improved. The fatigue life of the multi-fulcrum crankshaft is predicted to reach 30,000 h by finite element analysis. This study would provide a theoretical basis for further development of the LSR pump.
“…Because of this, it is simple to derive the equations of motion for the JuR by first determining the equations of motion for each leg and the upper hull separately, then integrating them, while enforcing the constraints of deformation compatibility and force equilibrium at the intersections of the legs and the hull. Dynamic equations of motion-related topics are discussed in detail in [19][20][21][22][23][24], where the dynamic motion model is impacted by internal elements, including stress and stiffness [25], as well as environmental elements [26]. There are six degrees of freedom at each nodal point:…”
Section: Mathematical Model Of the Jacking Control Systemmentioning
Oil and gas projects differ from regular investment projects in that they are frequently large-scale, categorised as vital national projects, highly technological, and associated with significant risks. Drilling rigs are a crucial component of the oil and gas sector and the majority of the systems and equipment aboard drilling rigs are operated automatically. Consequently, it is crucial to address the topic of an advanced control theory for off-shore systems. Network technology connected to control is progressively being used to replace outdated technologies, together with other contemporary technologies. In this study, we examine how to adapt a networked control jacking system to the effects of internal and external disturbances with a time delay, using a Fuzzy controller (FC)-based particle swarm optimisation. To demonstrate the benefit of the proposed approach, the developed Fuzzy Particle Swarm Optimisation (FPSO) controller is compared with the fuzzy controller. Finally, the results from simulations and experiments utilising Matlab software and embedded systems demonstrate the suitability of the proposed approach.
“…Material data are discussed by Montestruc, A. N. 13 The state-of-the art for this class of component is now composed by a rack and 7 ÷ 8 teeth spur pinion. 12,[14][15][16] Unfortunately, having a low number of teeth implies a very high contact pressure. Indeed, the Involute (INV) contact radius ρ y decreases as contact becomes closer the base diameter d b , where ρ y = 0.…”
Section: Introductionmentioning
confidence: 99%
“…ISO6336 series and ANSI AGMA) or by adopting Finite Element Method (FEM) (e.g. Zhou, H. et al 11 use FEM to assess the leg body, Ahmed, K. S. et al 12 perform the assessment of the tooth root of a jack/up rack using FEM). Material data are discussed by Montestruc, A. N. 13 Figure 1.A scheme of a jack-up.…”
A jack-up is an off-shore platform that, thanks to the capability of lowering its legs, is capable to elevate its hull from the water. Typically, the movement of the leg and the subsequent emersion of the jack-up is ruled by a rack-pinion system in which the pinion is a low number of teeth (typically 7 ÷ 8) spur gear. Recently, in order to reduce the contact pressure, it has been proposed to substitute the classical Involute (INV) profile of the pinion by a Multi Radius (MR) one. However, due to their intrinsic differences, the classical INV theory cannot be adopted directly as means to study the behaviour of the MR profile. Therefore, a Tooth Contact Analysis (TCA) procedure for the initial evaluation of a rack and MR pinion system is presented here. The aforementioned TCA enables to calculate relevant gear quantities (e.g. forces, velocities and contact pressure). Furthermore, thanks to the concept of coupled Transmission Error functions, it allows to evaluate, in the initial design phase, if the rack and pinion mesh occurs without impacts.
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