The Dynamic Response Simulation Of Vehicles And Typical Lashing System On Board Ro-ro Ships

Ro-Ro ships achieved “door-to-door” direct transport that is efficient and low-cost.But it's not always safe on voyage Because of its high mass center.As the transportation experience shows,the effective reinforcement of transport vehicles is important to the ship safety.Otherwise,the movement or collision of transport vehicles would cause listing and capsizing due to the shifting of the cargo.It takes a long time and is dangerous to carry out experiments.While the development of virtual prototyping technology makes it possible to study the problem.A truck was selected as the test object,and a series of experiments were carried out,including the determination of mass center of the truck and the determination of natural frequency and damping ratio of the suspension system.With the known truck parameters,the truck model was built in Adams/View.The leaf spring model was built by the discrete beam method which could take into account the accuracy and speed.The truck model was validated and the quality parameters and the natural frequency of the suspension system were consistent with the actual measurement results.The truck-ship-lashing model was built through establishing the ship model and lashing model.The ship was established as a rigid plate and the lashings was established as springs.The angle of the springs to the horizontal plane and the vertical plane was 45?.The ship was subjected to an excitation with a roll amplitude of 30?,a pitch amplitude of 8?and a period of 9s and the curve of lashing load vs time was got.The lashing load was cyclically changed,and the cycle was the same as the excitation period.The phase of the load of left and right side lashing was 180?.Then the effects of excitation period,lashing stiffness,preload,friction coefficient,suspension locked or not and truck orientation on the maximum lashing load were studied.The results showed that the maximum lashing load decreased with the excitation period increasing,which was an important factor affecting the maximum lashing load;the maximum lashing load increased with the lashing stiffness increasing in a certain range,but lateral slip of the truck would be too large if lashing stiffness was too small;the lashing preload had little effect on the maximum lashing load;the maximum lashing load and lateral slip decreased with friction coefficient increasing;the maximum lashing load decreased if the suspension was locked,but there was large fluctuation on the lashing load;placing the truck along y' of the ship would make the maximum lashing load decreased.