Initial response mechanism and local contact stiffness analysis of the floating two-stage buffer collision-prevention system under ship colliding

2021 ◽  
pp. 136943322098610
Author(s):  
Kai Lu ◽  
Xu-Jun Chen ◽  
Zhen Gao ◽  
Liang-Yu Cheng ◽  
Guang-Huai Wu
Keyword(s):  
Kinetic Energy ◽  
Impact Force ◽  
Contact Stiffness ◽  
Impact Angle ◽  
Bridge Pier ◽  
Two Stage ◽  
Collision Prevention ◽  
Prevention System ◽  
The Impact ◽  
Depth Curves

A floating two-stage buffer collision-prevention system (FTBCPS) has been proposed to reduce the impact loads on the bridge pier in this paper. The anti-collision process can be mainly divided into two stages. First, reduce the ship velocity and change the ship initial moving direction with the stretching and fracture of the polyester ropes. Second, consume the ship kinetic energy with the huge damage and deformation of the FTBCPS and the ship. The main feature of the FTBCPS lies in the first stage and most of the ship kinetic energy can be dissipated before the ship directly impacts on the bridge pier. The contact stiffness value between the ship and the FTBCPS can be a significant factor in the first stage and the calculation method of it is the focus of this paper. The contact force, the internal force and the general equation of motion have been given in the first part. The structure model of the ship and the FTBCPS are then established in the ANSYS Workbench. After that, 38 typical load cases of the ship impacting on the FTBCPS are conducted in LS-DYNA. The reduction processes of the ship kinetic energy and the ship velocity in different load cases have been investigated. It can be summarized that the impact angle and the ship initial velocity are the main factors in the energy and velocity dissipation process. Moreover, the local impact force-depth curves have also been studied and the impact angle is found to be the only significant factor on the ship impact process. Next, the impact force-depth curves with different impact angles are fitted and the contact stiffness values are accordingly calculated. Finally, the impact depth range, the validity of the local simulation results and the consistency of the fitted stiffness value are verified respectively, demonstrating that the fitted stiffness values are applicable in the global analysis.

Analysis on the Impact Force of a Ship Colliding with a Bridge Pier

2012 ◽  
Vol 193-194 ◽  
pp. 693-701
Author(s):  
Jian Guo Ding ◽  
Zhi Qiao
Keyword(s):  
Mechanical Model ◽  
Mass Velocity ◽  
Impact Force ◽  
Impact Angle ◽  
Bridge Pier ◽  
Velocity Coefficient ◽  
The Impact

Because many accidents in China involve a ship in a barge fleet colliding with a bridge pier, determining the impact force of the ship is important. To obtain an equation that describes the impact force of a ship colliding with a bridge pier, a mechanical model of the collision is simplified, and the results from other researchers are applied. Based on the equation, it is found that the impact force of a ship colliding with a bridge pier is not only relevant to the mass，velocity, board thicknesses of the ship, and the impact angle, but also to the remaining velocity coefficient. It has been demonstrated that the result from the proposed equation in this paper is in accordance with that of Gkss’s test in Wosin G theory.

scholarly journals Theoretical and Numerical Investigation on Perforation Resistance of Monolithic and Segmented Concrete Targets with Steel Liners under Normal Penetration

2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Yi Cheng ◽  
Zhimin Xiao ◽  
Yuan Zhang
Keyword(s):  
Kinetic Energy ◽  
Contact Stiffness ◽  
Projectile Energy ◽  
Initial Kinetic Energy ◽  
Residual Velocity ◽  
Velocity Prediction ◽  
Steel Liner ◽  
The Impact ◽  
First Time ◽  
Better Than

Steel-concrete composites are important armor protective materials with the increasing power of precision-guided weapons. In this study, the formula of residual velocity as well as the ratio between residual and initial kinetic energy (Er/E0) for concrete targets with a rear steel liner was derived. By establishing finite element models of steel liner concrete targets through ANSYS/LS-DYNA, the effect of the steel liner layout on the perforation resistance was analyzed for both monolithic and segmented concrete targets, which were compared in terms of projectile kinematics characteristics, projectile energy consumption, and target damages. Four main conclusions were drawn: (1) a residual velocity prediction model of concrete targets with a rear steel liner was accurately proposed for the first time when velocity reduction coefficient η was 0.15 and the derived Er/E0 could be used to evaluate their corresponding perforation resistance; (2) moving back the steel liners enhanced the perforation resistance of both monolithic and segmented targets, but the performance of the latter was inferior to that of the former, which was reduced by 10%–16% under the same conditions; (3) during middle- and low-speed perforations, the projectile impact force was more influenced by the contact stiffness than the impact velocity; and (4) regarding the segmented targets, the perforation resistance of the 2nd target was better than the 1st target, which consumed about 10%–20% more projectile kinetic energy.

scholarly journals Effective Formula for Impact Damping Ratio for Simulation of Earthquake-induced Structural Pounding

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 347 ◽  
Author(s):  
Seyed Mohammad Khatami ◽  
Hosein Naderpour ◽  
Rui Carneiro Barros ◽  
Anna Jakubczyk-Gałczyńska ◽  
Robert Jankowski
Keyword(s):  
Kinetic Energy ◽  
Impact Force ◽  
Damping Ratio ◽  
Dissipated Energy ◽  
Force Model ◽  
Single Collision ◽  
Structural Pounding ◽  
Impact Forces ◽  
The Impact ◽  
Impact Damping

Structural pounding during earthquakes may cause substantial damage to colliding structures. The phenomenon is numerically studied using different models of collisions. The aim of the present paper is to propose an effective formula for the impact damping ratio, as a parameter of the impact force model used to study different problems of structural pounding under seismic excitations. Its accuracy has been verified by four various approaches. Firstly, for the case of collisions between two structural elements, the dissipated energy during impact has been compared to the loss of kinetic energy. In the second stage of verifications, the peak impact forces during single collision have been analyzed. Then, the accuracy of different equations have been verified by comparing the impact force time histories for the situation when a concrete ball is dropped on a rigid concrete surface. Finally, pounding between two structures during earthquakes has been studied. The results of the analysis focused on comparison between dissipated and kinetic energy show relatively low errors between calculated and assumed values of the coefficient of restitution when the proposed equation is used. In addition, the results of the comparison between experimentally and numerically determined peak impact forces during single collision confirm the effectiveness of the approach. The same conclusion has been obtained for the whole impact time history for collision between a ball and a rigid surface. Finally, the results of the comparative analysis, conducted for pounding between two structures during an earthquake, confirm the simulation accuracy when the proposed approach is used. The above conclusions indicate that the proposed formula for impact damping ratio, as a parameter of impact force model for simulation of earthquake-induced structural pounding, is very effective and accurate in numerical simulations in the case of different scenarios.

scholarly journals Study of Passive Protective Net Protecting the Rockfall Caused by Open-Pit Blasting on High and Steep Slope

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhiyu Zhang ◽  
Qingyun Qian ◽  
Jianguo Wang ◽  
Haoshan Liu ◽  
Ke Liang ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Impact Force ◽  
Impact Resistance ◽  
Steep Slope ◽  
Interaction Time ◽  
Open Pit ◽  
Buffer Time ◽  
The Impact ◽  
Impulse Force ◽  
High And Steep Slope

In order to prevent rockfall caused by open-pit blasting on the high and steep slope and ensure that the passive protective net structure has sufficient impact resistance, the mechanism of blasting flyrock causing rockfall is analyzed by using ANSYS/AUTODYN to establish the model of rockfall and passive protective net; at the same time, the influences of protective net size, rockfall kinetic energy, and rockfall size to the protective effect were also studied. The results show that under the condition of the same rockfall kinetic energy and rockfall size, the larger the size of the protective net, the longer the buffer time, and the impact force that net can sustain is greater; by assuming the protective net size and rockfall size to be a constant, the greater the rockfall kinetic energy, the less the interaction time between rock and net, and the greater the impulse force that net can suffer; similarly, by keeping the protective net size and the kinetic energy of rockfall to be a constant, it is found that the larger the size of the rockfall, the larger the interaction area and longer interaction time with the net, and the less net will be disrupted; the protective net used in the mine can intercept the rockfall caused by flyrock in blasting process effectively and ensure the safety of villager at the foot of the mountain.

Research of Performance about Ceramic Coating on Aluminum Bumper to Resist Hypervelocity Impact

2013 ◽  
Vol 577-578 ◽  
pp. 629-632
Author(s):  
Gong Shun Guan ◽  
Qiang Bi ◽  
Yu Zhang
Keyword(s):  
Kinetic Energy ◽  
Optimum Design ◽  
Critical Thickness ◽  
Ceramic Coating ◽  
Impact Angle ◽  
Hypervelocity Impact ◽  
Front Side ◽  
Gas Gun ◽  
Whipple Shield ◽  
The Impact

Shield structure based on ceramic coating on aluminum bumper was designed, and a series of hypervelocity impact tests were practiced with a two-stage light gas gun facility. Impact velocities were varied between1.5km/s and 5.0km/s. The diameter of projectiles were 3.97mm and 6.35mm respectively. The impact angle was 0°. The damage of the ceramic coating on aluminum bumper under hypervelocity impact was studied. It was found that the ceramic coating on aluminum bumper could help enhancing the protection performance of shield to resist hypervelocity impact. The results indicated when the ceramic coating is on the front side of aluminum bumper, it was good for comminuting projectile and weakening the kinetic energy of projectile. For a certain aluminum bumper, existing a critical thickness of ceramic coating in which capability of Whipple shield to resist hypervelocity impact is the best. On this basis, the proposal of the optimum design for ceramic coating on aluminum bumper was made.

INFLUENCE OF THE IMPACT ANGLE OF A SOLID PARTICLE JET ON THE EROSION WEAR OF 38GSA AND HARDOX 500 STEEL

Tribologia ◽  
2017 ◽  
Vol 273 (3) ◽  
pp. 85-90 ◽  
Author(s):  
Bazyli KRUPICZ ◽  
Wojciech TARASIUK ◽  
Jerzy NAPIÓRKOWSKI ◽  
Krzysztof LIGIER
Keyword(s):  
Mechanical Properties ◽  
Kinetic Energy ◽  
Solid Particle ◽  
Quartz Sand ◽  
Impact Angle ◽  
Erosion Wear ◽  
Sand Particles ◽  
Work Of Deformation ◽  
The Impact

The paper investigated the influence of the impact angle of a solid particle jet on the erosion wear of 38GSA and Hardox 500 steel. The basis of the analysis was the assumption of the existence of a correlation between mechanical properties of the material, represented by the work of deformation (P) determined from the stressstrain diagram (U). The impact angle of quartz sand particles (30, 60, and 90 °) was considered through the separation of kinetic energy of particles impacting the eroded surface perpendicularly and tangentially.

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