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Numerical simulation of non-linear wave tank based on the ale algorithm

INTERNATIONAL JOURNAL OF COMPUTER APPLICATIONS IN TECHNOLOGY 2013年第4期47卷 343-350页

作者： Zhu, Feng Zhu, Weihua Wang, Y. N. Fang, B. Zhao, S. L. Hohai Univ Coll Sci Nanjing 210098 Jiangsu Peoples R China Hohai Univ Coll Harbour Coastal & Offshore Engn Nanjing 210098 Jiangsu Peoples R China

Numerical Wave Tank (NWT) becomes more and more prominent in the corresponding scientific research. On the basis of the Navier-Stokes (N-S) equation, the early application be adopted for discretising and calculating the specific region is by Volume of Fluid (VOF) and Finite Volume Method (FVM) method. But with the non-linear increasing size of calculation quantity, it becomes difficult to meet the requirements for engineering. However, ale algorithm and SPH algorithm developed in recent years have the tendency to be mature enough to meet the engineering requirements. The calculation model of three-dimensional NWT is built by ale algorithm as an example in this paper, and the results are compared with theoretical solution and experiment. The comparison has proved that ale algorithm matches with the theoretical solution and experiment, and is suitable for engineering use.

关键词： water tank ale algorithm Stokes wave

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Uncertainty due to discretization on the ale algorithm for predicting water slamming loads

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MARINE STRUCTURES 2021年 80卷 103086-103086页

作者： Wang, Shan Islam, Hafizul Guedes Soares, C. Univ Lisbon Ctr Marine Technol & Ocean Engn CENTEC Inst Super Tecn Lisbon Portugal

Numerical uncertainty due to discretization on the Arbitrary Lagrangian-Eulerian (ale) Finite Element method is investigated in the study. The paper quantifies uncertainty using two ITTC recommended methods, and also applies a constant Courant-Friedrichs-Lewy (CFL) number based discretization approach, instead of performing the independent grid and time-based discretization recommended by ITTC. As a case study, water entry of a flat bottom rigid and flexible plate is simulated considering various entry velocities. The total slamming loads and structural responses on both the rigid and elastic bottom plates are predicted and validated against available experimental data. Results indicate that numerical errors due to discretization differ in the various parameters and from case to case. They do affect the analysis of slamming loads and associated structural responses, and the hydroelasticity analysis as well. The hydroelasticity effects on the slamming force generally increase as the entry velocity increases, however, the quantitative results differ much for models with different grids. For example, when the hydroelasticity effect is estimated using the finer model, the deviation of the total slamming force on the elastic plate relative to the one on the rigid body are 56%, 57%, and 63% respectively for the three constant entry velocities, whereas the estimations are -27%, -4% and 3% with the coarser model. The study concludes that the uncertainty due to discretization in ale is not just case-specific, but also parameter specific. The uncertainty quantification procedures with a constant CFL number based refinement are recommended to investigate the uncertainty comparing to the individual grid and time step study, in particular for the ale solution where the time step is adjusted automatically as the grid changes. Thus, consideration should be given to updating the ITTC guidelines to incorporate the constant CFL based discretization approach.

关键词： Numerical uncertainty Constant CFL based Approach ale algorithm Water slamming load Flat bottom plate

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Modeling and Analysis of Numerical Wave Tank Based on the ale algorithm

Modeling and Analysis of Numerical Wave Tank Based on the AL...

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4th International Conference on Modelling,Identification and Control(ICMIC 2012)

作者： Zhu Feng, Hohai university, College of science & College of Harbour, Coastal and Offshore Engineering. Nanjing, CHINA.Zhu We-iHua, Professor of Hohai university, Be now with the Department of Physics, College of science. Nanjing, CHINA.Fan Jun, be with the Hohai university, College of Harbour, Coastal and Offshore Engineering.Fang Bo, be with the Hohai university, College of science. Zhao Kun, be with the Hohai university, College of DaYu.

Recently, with the development of coastal engineering, numerical wave tank is more and more prominent in the corresponding scientific research and becomes one of the hot points in fluid dynamics. Based on the Navier-Stokes (N-S) equations, which is the basic equation of fluid mechanics, the early application is adopted for discretizing and calculating the solving region by VOF (Volume of Fluid) and FVM (Finite Volume Method) method. But with the increasing size of calculation, the data storage capacity and the number of equations for calculating appears non-linear growth, it has been difficult to meet the requirements for engineering. ale algorithm and SPH algorithm developed in recent years have tended to be mature to meet the engineering requirements by fast and precision calculation. The simulation of three-dimensional numerical wave tank is built by ale algorithm as an example in this artical and the results of calculation are compared with non-linear second-order Stokes wave and experiment. The comparison is proved that ale algorithm is consistent with the theoretical solution and experiment.

关键词： Water tank ale algorithm Stokes wave

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Research on the Performance of a Mooring Platform Under the Collision of Icebergs

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China Ocean Engineering 2025年第1期39卷 43-57页

作者： ZHANG Yan ZHANG Song-bao WANG Yi-tao ZHAO Wei-dong GUI Hong-bin School of Ocean Engineering Harbin Institute of TechnologyWeihaiWeihai 264209China China Ship Scientific Research Center(CSSRC) Wuxi 214082China College of Shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

In the process of developing oil and gas resources in the Arctic,the impact of icebergs can pose a considerable threat to the structural safety of semi-submersible mooring platforms in ice *** the basis of the arbitrary Lagrangian Eulerian(ale)algorithm,a numerical model for the interaction between an iceberg and a semi-submersible mooring platform is built in this ***,a mooring system with a link element is designed and *** ice material model for the target iceberg is built and validated.A numerical model for the interaction between an iceberg and a semi-submersible mooring platform is then built.A parametric study(cable angle,tension angle and number of cables)is carried out to study the performance of the mooring *** collision process between the semi-submersible mooring platform and the iceberg in the polar marine environment can be predicted by the present numerical model,and then the optimal mooring arrangement scheme can be *** research results in this work can provide a reference for the design of mooring systems.

关键词： ale algorithm semi-submersible platform iceberg collision mooring system

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Numerical study on separation shock characteristics of pyrotechnic separation nuts

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ACTA ASTRONAUTICA 2018年 151卷 893-903页

作者： Zhao, Hongda Liu, Wei Ding, Jifeng Sun, Yi Li, Xiao Liu, Yizhi Harbin Inst Technol Harbin 150001 Heilongjiang Peoples R China China Acad Space Technol Beijing 100094 Peoples R China

This paper establishes a finite element model of pyrotechnic separation nuts and simulates the whole separation process based on the explicit dynamic codes LS-dyna with Arbitrary Lagrange-Euler (ale) algorithm. The separation shock generated in the unlocking process is analyzed in detail and the results reveal that the pyrotechnic explosion shock and strain energy shock are two sources for the whole separation shock. Besides that, the influence of prestress on the separation shock and its two shock sources is also researched. The results show that the prestress could strengthen all three shocks, especially the strain energy release shock. This paper also compares the shock response spectrum (SRS) of the three shocks and finds that the SRS of separation shock is equal to the envelope of the SRS of pyrotechnic explosion shock and strain energy release shock. In the model of this paper, the pyrotechnic explosion shock plays a dominant role in the frequency range of 100 Hz to 10 KHz. The conclusions got in this work are helpful to insight the mechanism of separation shock and can provide a reference for the design of separation nuts.

关键词： Pyrotechnic separation nuts ale algorithm Separation shock Prestress Shock response spectrum

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Dynamic simulation of sugarcane milling process based on Arbitrary Lagrangian-Eulerian algorithm

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BIOSYSTEMS ENGINEERING 2021年 206卷 162-174页

作者： Qiu, Minmin Meng, Yanmei Qin, Johnny Chen, Jie Guangxi Univ Coll Light Ind & Food Engn Nanning 530004 Peoples R China Guangxi Univ Sci & Technol Sch Mech & Transportat Engn Liuzhou 545006 Peoples R China Guangxi Univ Sch Mech Engn Nanning 530004 Peoples R China CSIRO Resource 1 Technol Court Pullenvale Qld 4069 Australia

Understanding the process of the sugarcane milling is important for improving sugar extraction. The Arbitrary Lagrangian-Eulerian algorithm within LS-DYNA was successfully used for the first time to simulate the dynamic process of milling. The predictions of the numerical model were validated using experimental crushing data from a previous study and dynamic process of milling was examined in detail. The draining performance during milling needs to be carefully considered. It was found that the deformation of the sugar-cane in the XY cross-section under loads consisted of two main phases;compression and expansion with reabsorption mostly occurring during the expansion phase. The feeding side of the nip is the main area for the draining of juice. A sensitivity analysis of param-eters influencing load and pressure was conducted. This research method could be applicable to similar engineering problems where there is contact, collision, extrusion, large displacement, and large deformation. (c) 2021 IAgrE. Published by Elsevier Ltd. All rights reserved.

关键词： ale algorithm Sugarcane milling Process simulation Sensitivity analysis

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Shock Response Analysis of a Large LNG Storage Tank Under Blast Loads

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KSCE JOURNAL OF CIVIL ENGINEERING 2018年第9期22卷 3419-3429页

作者： Zhang Rulin Jia Juanjuan Wang Huaifeng Guan Youhai China Univ Petr East China Coll Pipeline & Civil Engn Qingdao 266580 Peoples R China China Mobile Commun Grp Shandong Co Ltd Qingdao Branch Qingdao 266000 Peoples R China Xiamen Univ Technol Sch Civil Engn & Architecture Xiamen 361000 Peoples R China

Ensuring the safe operation of large LNG storage tank projects under blast loads is very important. First, using LS-DYNA software, numerical simulations of air blast wave propagation are studied with the ale algorithm and fluid-solid coupling theory. A new corrected formula for the peak overpressure is proposed based on the numerical results, and its accuracy is verified by comparing the numerical results with the empirical formula and test results. Then, a finite element model of a large LNG storage tank is built, assuming that the explosion source is located 10 m away from both the ground and the tank wall. This model is used to analyse the overpressure and dynamic response of the outer concrete tank and to predict the TNT equivalent quantity that the tank can withstand. The results show that the tank wall facing the burst loads is in a more dangerous state and that the principal tensile stress increases approximately linearly with increasing TNT equivalent quantity. When the TNT equivalent quantity reaches 2.5 t, concrete element failure occurs on the centre facing the explosions, and the outer tank structure is damaged. The conclusions can provide a reference for the blast-resistant design of large LNG storage tanks.

关键词： LNG storage tank explosions peak overpressure formula numerical simulation ale algorithm dynamic response

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Entrance shape design of spread extrusion die for large-scale aluminum panel

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INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 2019年第5-8期101卷 1725-1740页

作者： Liu, Zhiwen Li, Luoxing Yi, Jie Wang, Guan Univ South China Sch Mech Engn Hengyang 421001 Peoples R China Hunan Univ State Key Lab Adv Design & Mfg Vehicle Body Changsha 410082 Hunan Peoples R China

The entrance shape of spread die plays a crucial role in the quality control of large-scale aluminum panel production. The conventional design of spread die is generally based on the experience and expertise of the die designers or costly plant trials. Thus, it is difficult to guarantee the material flow through subsequent feeder die with the same velocity and ensure the die strength. In this work, the extrusion processes of three spread dies with different entrance shapes used generally in the real extrusion production for large-scale aluminum panel were investigated by FE simulations. Firstly, 3D-FE models for simulating the extrusion processes of the three spread dies were established by using HyperXtrude software based on ale algorithm. Then, the effects of different die designs on the material flow behavior, extrusion load, temperature, residual stress distribution, and die deflection were synthetically studied by analyzing and comparing the simulated results. Finally, the optimal die was manufactured and corresponding extrusion experiment was carried out on a 2600-t extrusion press. The simulation and experimental results show that the die 2 with fan-shaped entrance was the optimum one among the three spread dies, where the minimum required extrusion load, uniform flow velocity at the die exit, minimum residual stress in extruded profile, and minimum die deflection were obtained. This study could provide effective guidance on the entrance shape design of spread extrusion die for the large-scale aluminum panel.

关键词： Large-scale aluminum panel Spread extrusion die Entrance shape ale algorithm Simulation

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RESEARCH ON DAMAGE CHARACTERISTICS AND PROTECTIVE STRUCTURE DESIGN OF STEEL PONTOONS UNDER NEAR-FIELD EXPLOSION LOAD

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BRODOGRADNJA 2022年第4期73卷 53-77页

作者： Li, Kai Zhao, Zhichao Chang, Songliang Bao, Jiawei Yuan, Zhijiang Jiang, Xiaogang Dalian Univ Technol Sch Naval Architecture & Ocean Engn Dalian 116024 Peoples R China Dalian Naval Acad Dept Nav Dalian 116001 Peoples R China

The focus of this paper is to investigate the damage characteristics and protective structure design of pontoons as an important barrier for the protection of ports. Two types of protective measures of pontoons are investigated:filling tanks with water and installing springs in tanks. In this paper, the damage characteristics of two types of pontoon side structures under the action of near-field explosion loads are simulated by using LS-DYNA explicit dynamic analysis software and the ale algorithm. According to the numerical experiment results for filling different volumes of water in the side tanks, the volume of water for the minimum deformation of the shell plate is 100%, and for the first longitudinal bulkhead, it is 30-40%. Moreover, by applying weights to their deformations based on the actual explosion-proof performance requirements of the shell plate and the first longitudinal bulkhead, the pontoon side structure with the best explosion-proof performance can be obtained. The plastic deformation of the pontoon structure equipped with different types of springs is an order of magnitude smaller than that of the ordinary structure and of the pontoon structure filled with a water medium in the positive tanks. The explosive shock wave energy absorbed by the pontoon is effectively reduced by the addition of water or springs to the protective tanks. The minimum energy absorbed by the pontoon structure with water added in the protective tanks is 18.31% of the energy absorbed by the ordinary structure, and the corresponding volume ratio of water added in the protective tanks is 100%. The pontoon structure with springs in the side protection tanks absorbs only 7.2% of the energy absorbed by the ordinary structure. Both new side protection structures have demonstrated excellent explosion-proof performance.

关键词： Near-field explosion pontoon ale algorithm structural design water tank spring

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Ground Vibration Test and Dynamic Response of Horseshoe-shaped Pipeline During Tunnel Blasting Excavation in Pebbly Sandy Soil

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GEOTECHNICAL AND GEOLOGICAL ENGINEERING 2020年第4期38卷 3725-3736页

作者： Guan, Xiaoming Wang, Xuchun Zhu, Zhen Zhang, Liang Fu, Hongxian Qingdao Univ Technol Sch Civil Engn Qingdao 266033 Peoples R China Southwest Jiaotong Univ Sch Civil Engn Chengdu 610031 Peoples R China Beijing Jiaotong Univ Sch Civil Engn Beijing 100044 Peoples R China

In order to ensure the safety of horseshoe-shaped pipeline during tunnel blasting excavation, the vibration test and dynamic response of horseshoe-shaped pipeline were investigated. The velocity and frequency of tunnel blasting vibration were analyzed. Sodev's empirical formula was used for regression analysis of the velocity of blasting vibration. 3D numerical model of a horseshoe-shaped pipelines was established with ale algorithm using ANSYS/LS-DYNA. The propagation law of a blasting seismic wave was analyzed, and the transverse and longitudinal vibration response characteristics of pipelines under tunnel blasting vibration were studied. The velocity of the pipeline increases gradually and the frequency tends to decrease with the decrease of the distance away from the explosion source center under the same charge. The principal frequency of vibration in the Z direction is mainly distributed from 50 to 80 Hz, which is difficult to generate resonance with the pipelines. The maximum relative error between the simulated and measured velocity of X, Y and Z directions was 8.2%. It was reliable to study the dynamic response of pipelines under blasting vibration based on this numerical model. The blasting seismic wave first reached the bottom of the pipeline right above the explosive. Subsequently, seismic waves propagated along the transverse and the longitudinal axes of the pipeline, and the pressure on the pipeline increased gradually. And when it attenuated completely in the soil, the pipeline stopped its response. The peak value of tensile stress of each element of the vault is the largest. However, the velocity of the bottom plate and the arch roof of pipeline are the largest. The peak values of velocity and tensile stress exist in 0 to 4 m away from the explosion source, and gradually decrease as the distance away from the explosion source increases.

关键词： Horseshoe-shaped pipeline Tunnel blasting Numerical simulation ale algorithm Vibration response

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