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Spar platform is one of the major equipment for deep-sea oil and gas resource development, one of the mooring system is the positioning system of the deep-sea platform mooring system will appear, when the mooring platform significantly floating body movement, relaxation - tension changes cause mooring line tension increases rapidly, and may endanger the safety of the deep-sea platform production. Impact for the process of deep-sea mooring system relaxation - tension tension, the main work and conclusions are as follows: (1) consider Mohammad Behbahani Negad research work on the basis of the level of tension within the cable and position, using the Taylor series expansion expression of curvature and tension cable, the establishment of a continuum model of relaxation and tension both cases, the stress wave theory to analyze the level of tension in the cable within the wave number, ropes coordinates and other parameters of the the cable stress wave propagation characteristics proved this paper, we consider the reasonableness of the cable tension and curvature change. (2) According to the basic theory of the stress the Porgy of this theory and nonlinear dynamics, calculated cables in the three states of relaxation, relaxation - tension and tension of movement and tension of the cable, the comparative analysis of the the cable three sports state distinction found that the three states, the movement of the rope structure characteristics, maximum tension and the extent of the damage to the structure is not the same. The relaxation - tension state, the lateral movement of the rope jumping, the spikes and octave ingredients tension mutation. The impact relaxation - the tension generated when the tension is slack, 5 times, 2.4 times the tensioning situation easily cause the strength of the destruction of the cable, to shorten the fatigue life. (3) According to the theory of impact dynamics, the floating body mooring platform - cable system coupled analysis, given the system's relaxation area boundary curve and tension, and influencing factors are analyzed. The results show that the cables - the floating body itself, system parameters, and external load conditions change, such as the the nondimensional displacement ratio, or the damping ratio is changed, it will cause the system in transition between the relaxation - the tensioning region, thereby causing the impact tension within the cable . The maximum dynamic tension in the cable within the wave height, wave frequency, the pre-tension increases with increasing cable length decreases. (4) using the experimental method, the rope immersed in a quasi-static fluid impact tension study observed that the shock in the cable tension, and to prove the necessity of the existence and the study of this problem of impact tension. At the same time, also studied the impact factors of maximum tension in the cable. The results show that under the same conditions, the maximum tension of the cable with the endpoint excitation frequency and excitation amplitude, cable stiffness, diameter of cable, cables and the elastic modulus increases with increasing cable length decreases. The experimental verification of the correctness of theoretical calculations. (5) the impact of the air impact tension experiments and water tension experiment comparative analysis, given the characteristics of the cable impact load occurs when the cable tension: the impact load occurs at the excitation end impact tension becomes large rapidly, and the tension in high frequency components, while the negative tension. These can be used as a judgment based on whether the impact load rope. In addition, the impact load occurs in the incentives end, which requires the actual design to strengthen the mooring point near the cable strength, in order to ensure the safety of the mooring system.
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