Dynamic Response Of Rigid Thin Plate In Wave Field

Very Large Floating Structures(VLFS)has been highly concerned by scholars at domestic and foreign,but so far people's understanding of Very Large Floating is not clear enough.The series of problems that the definition of Very Large Floating and the relationship between the dynamic response law of Very Large Floating and structural scales are far from solved by the independent or combined action of power elements,such as wave,current,wind,ice,etc.There is important basic significance for the practical application of VLFS that accurately predicting the VLFS environment load,motion and dynamic response laws and clarifying the similarities and differences between the hydrodynamic characteristics of VLFS and conventional floating bodies.Based on the physical model test,the dynamic response of a rigid sheet in a wave field was studied.In the case of regular wave condition and irregular waves condition,the motion characteristics and force characteristics of the rigid thin-plate with constraint conditions and the influence on the wave field behind the thin-plate were respectively measured and analyzed,and the effect of the relative size of the thin-plate,the relative wave height and the water depth on the mooring force,the motion response,the distribution of the back wave height,and the wave pressure distribution of the thin-plate were analyzed.Finally,it compares and analyzes the regularity of regular and irregular conditions.The results showed that:As far as the mooring force of a large moored sheet is concerned: the four components of surge,heave,roll,and pitch are the main motion components of large thin-plate.The other two motion components are very small.When the irregular wave acts,all the motion components are dominated by low frequency(below the wave frequency),and the components of the heave motion contain wave components.The motion component of large thin-plate decreases with the increase of relative plate length.The relative plate length,when the motion component reaches the fixed value,is relative to the relative water depth.From the angle of large floating body motion,it can be considered that,when the length and width ratio is 4:1,the relative water depth is d/B=0.06 to 0.08,and the relative length of the plate is more than 7,and it can be seen as a VLFS.As far as the mooring force of a large moored sheet is concerned: The mooring force of large thin-plate decreases with the increase of relative plate length.The relative plate length,when the mooring force reaches the fixed value,is relative to the relative water depth.From the angle of large floating mooring force,it can be considered that,when the length and widthratio is 4:1,the relative water depth is d/B=0.06 to 0.08,and the relative length of the plate is more than 7,and it can be seen as a VLFS.As far as the wave pressure on a large plate floor is concerned: The point pressure distribution on the edge line of thin plate centerline or wave direction is decreasing from the head to the tail.From the angle of the wave pressure on a large plate floor,it can be considered that,when the length and width ratio is 4:1,the relative water depth is d/B=0.06,and the relative length of the plate is more than 5,and it can be seen as a VLFS.In terms of the post wave height distribution,the specific wave height of each point behind the plate decreases with the increase of the length of the relative plate when B/L < 3,and the specific wave height in the test range tends to be stable when the B/L is more than 3.When the relative plate length is reduced to near 1,the wave dissipation ability of the thin plate is significantly reduced.In summary,from the angle of the dynamic response of a large thin-plate,it can be considered that,when the length and width ratio is 4:1,the relative water depth is d/B=0.06~0.08,and the relative length of the plate is more than 7,and it can be seen as a VLFS.