Research On Explosive Welding Quality Simulation Based On SPH Method

Explosive welding has become a very important branch of metal processing technology because of its simple technology,low cost and excellent properties of composite metals.At present,China’s manufacturing output value has ranked first in the world,and the booming development of manufacturing industry has created a huge demand for composite materials,so the application prospect of explosive welding is bound to be very broad.However,the process of explosive welding is too fast and the energy conversion process is complex,so it is undoubtedly difficult to study the welding process by direct observation.At the same time,there are many parameters and processes which affect the quality of explosive welding,if each parameter is tested,the cost is too high and the time is longer.As a result,with the help of ANSYS/LS-DYNA finite element software and SPH method,this paper studies the influence of different technologies and parameters on explosive welding.By means of SPH method,the numerical simulation of copper-steel explosion welding is carried out,and the formation process of a single waveform is demonstrated and analyzed in combination with the theory.The process is gradually repeated,and finally appears as periodic wave-like interface.The simulation images show that the wave forming process simulated by SPH method is consistent with the description of jet indentation mechanism,which shows the effectiveness of the jet indentation mechanism in explaining the formation process of interface wave.In order to improve the final explosion welding quality,solve the problem of high noise and low efficiency,Cu is selected as flyer plate and Q235 steel as base plate,LS-DYNA software and SPH method are used to design uniform charge and ladder charge respectively,and the influence of charge mode and charge amount on the interface wave of explosive welding is studied.The results of uniform charge show that the impact pressure increases gradually along the detonation direction.The greater the amount of explosives,the greater the impact pressure and the larger the interface wave size.By changing the thickness of the beginning and end of explosives,four ladder charge are designed.The results show that ladder charge can effectively eliminate the uneven phenomenon of explosive welding interface wave,keep the interface wave size basically consistent,and save the amount of explosives.The waveform is best when the thickness of the start and end is 67.2mm and 42.0mm,respectively.In order to study the influence of the spacing of flyer plate and base plate on the quality of explosive welding,titanium plates and steel plates with a thickness of 2mm are selected to be spaced at 2.5,4.5,6-5,8.5 and 10.5mm respectively.With the help of LS-DYNA software,SPH-FEM coupling algorithm is adopted to conduct three-dimensional numerical simulation of the explosive cladding process.The explosion welding window is built based on material parameter.The simulation results show that the bonding quality of welding interface changes from low to high and from high to low with the increase of the spacing,which is in accordance with the existing experimental results.When the distance is 6.5mm,the simulation results of collision velocity are located inside the explosion welding window,indicating that the bonding quality is excellent and the simulation results are in accordance with the experiment SPH method is used to obtain the interface morphology of composite plate.The simulation results are consistent with the metallographic results.The simulation results show that a good explosion welding interface waveform can be obtained when the spacing is between 6.5mm and 8.5mm.With the help of LS-DYNA software and SPH-FEM coupling algorithm,the explosion welding process of stainless steel-steel is simulated by two-dimensional numerical simulation.The influence of the upper limit rule of spacing and initiation mode on the quality of explosive welding is studied.Simulation results show that when other conditions remain unchanged,the welding quality of the composite plate at the upper limit spacing of 6 mm is the best.At the same optimal collision speed,the amount of explosive can be saved,the simulation is consistent with the experimental results,the spacing follows the upper limit rule,the energy utilization rate of the explosive under the central detonation is high,and the central detonation is often used in the actual production of large area composite plates.The generation of boundary effect is theoretically analyzed,and it is considered that the end energy instability forms a negative collision angle,and then the boundary effect is formed.Numerical simulation is done for the extended flyer plate device,and the flying attitude of the flyer plate is demonstrated.Compared with the traditional explosive welding device,the simulation results eliminate the negative collision angle.It is shown that the boundary effect can be effectively eliminated by extending the length of the flyer plate,and the simulation results are in accordance with the theoretical analysis.