Study On The Optimization Of Abrasive Water Jet Cutting Parameters During Emergency Rescue

For disaster sites such as fire,earthquake and traffic accident,large rescue equipment is difficult to enter due to the particularity of the terrain and space,while small rescue equipment has low breaking efficiency,and it is impossible to quickly remove concrete components or other material obstacles.Abrasive water jet cutting technology does not produce open flame,high cutting efficiency,suitable for flammable and explosive environment,and relatively small volume,but its cutting performance needs to be further improved.In this paper,C35 concrete and Q235 steel plate,which are common in the disaster site,were selected as the target materials.Firstly,the influence of pre-mixed abrasive water jet on the process of cutting C35 concrete was studied,and the optimization method was proposed.The influence of jet pressure,transverse speed,impact angle and target distance on cutting performance was analyzed by single factor test and orthogonal test,and the prediction model of cutting depth was obtained by multiple linear regression analysis.The results show that the cutting depth is significantly different under the influence of different parameters,positively correlated with jet pressure and negatively correlated with transverse speed.The cutting depth increases first and then decreases with the increase of target distance,and the optimal target distance is 4mm.The cutting depth fluctuates with the impact Angle,and the optimal impact Angle is 80°.The influence degree of each process parameter on the cutting depth is not same,from large to small: jet pressure,transverse velocity,target distance.Based on the experimental data of cutting,the mathematical model of multiple linear regression of cutting depth of concrete with pre-mixed abrasive water jet was established.Secondly,the existing multipass cutting process is optimized to improve the abrasive water jet cutting performance.The difference between single cutting,multipass cutting in the same direction and alternate direction was analyzed by single factor experiment.The results show that the cutting depth decreases with the increase of transverse velocity,but the decreasing rate decreases.Under the same running time,the performance of multipass cutting in same direction is better than that of alternating one.The optimal cutting times of different shapes and materials are different.With the same thickness,the plate steel should be cut twice,while the tubular or columnar steel should be cut four times.The optimization effect increases with the thickness of the breaking material.Finally,the mathematical model of cutting depth under multipass cutting process of Q235 steel plate was constructed based on dimensional analysis,so as to better combine with the field and optimize cutting parameters.In order to make multipass cutting process better applied in the field,a portable electric bracket was designed to reduce the operation difficulty and danger of rescue workers.