Research On The Slamming Load On The Bow Of River-sea-going Ship

Due to water way’s restrictions, the river-sea-going ship’s ratio of breadth anddepth is greater than the value of2.5, which is the maximum of CCS’ river-sea-goingship standard at present. This means that the ship’s form is wide and flat. When theriver-sea-going ship sailing on the sea, slamming is becoming more susceptible. Inthis article, a method combining the model test and numerical simulation was used tostudy the river-sea-going ship’s slamming load problem. The main research contentsand conclusions are as follows:1. The drop tests of rigid wedge with deadrise of45were carried out. Theslamming process, slamming pressure history curves of measuring points andslamming pressure peaks were completely recorded. The conclusion is that thepressure peak of every measuring points was increasing with the drop speedincreasing of the rigid wedge. Along the vertical direction of the rigid wedge, theslamming pressure peak was decending. Along the longitudinal direction theslamming pressure peak basically the same.2. The transient dynamic analysis software which called ANSYS/LS-DYNA is usedto simulate the process of the slamming experiment of45rigid wedge. Thesimulation results are compared with the experimental results to validate thevalidity of using ANSYS/LS-DYNA numerical simulation to study the twodimensional rigid structures into water slamming problem.3. Based on the similarity theory, a river-sea-going ship model has been designed.The drop tests of the river-sea-going ship model under different height and trimwere carried out. The slamming process, slamming pressure history curves ofmeasuring points at the bottom and flare, slamming pressure peaks werecompletely recorded. Some conclusions have been obtained:(1) The pressure peak of each measurement point was increasing with the dropspeed increasing of the bow model.(2) When the trim angle is5, pressure peak of each measuring point reaches a maximum and then increase with the trim angle decreases.(3) When the trim angle is increasing, pressure peak of the measuring point onthe vertical line becoming gradually close.(4) When the model pour into the water vertically, the maximum pressure peakpoint is on the central longitudinal plane. When the trim angle is increasing,this point moves to the sides.4. ANSYS/LS-DYNA is used to simulate the process of the slamming experimentof the river-sea-going ship bow model. The simulation results are compared withthe experimental results to validate the validity of using ANSYS/LS-DYNAnumerical simulation to study the three dimensional rigid structures into waterslamming problem.5. ANSYS/LS-DYNA is used to simulate the process of slamming of the ship bowmodel with different trim angle and roll angle. Discusses the bottom and flareslamming pressure peak value law with the trim angle and roll angle variation.Some conclusions have been obtained:(1) For the bottom and flare measured point at the same frame, with the increaseof ship model bow trim angle, bottom slamming pressure peak valuedecreases, but the maximum slamming pressure peak area was the same;flare slamming pressure peak value remains the same, but the maximumslamming pressure peak area has a tendency to move outward to the flareroot area.(2) For the bottom and flare measured points at the same frame, with theincrease of ship model bow toll angle, bottom slamming pressure peak valueincrease, but the maximum slamming pressure peak area has a tendency tomove to the reverse side of roll direction; flare slamming pressure peakincrease, the maximum slamming pressure peak area has a tendency to moveoutward to the flare root area.