Design Of The Chassis For Sand Spraying And Research On The Walking Characteristics Of Its Tracks

Sand prevention and control is one of the major projects in the construction of ecological civilization in China.Among sand prevention and control equipment,self-propelled sand control equipment has obvious advantages such as high efficiency,low cost,and quick effect.Its sandy land passability directly determines the effect and efficiency of sand control operations.Wheeled walking sand control equipments are prone to slipping and sinking or even unable to travel when operating in sand.The tracked walking system has significant advantages such as low ground pressure and good cross-country passability,and is suitable for driving on soft and steep sand.Therefore,a tracked chassis for sand spraying operation was designed in this paper,and an ostrich-foot type sand track shoe was designed based on bionics design.Through the theoretical analysis of track shoe-sand interaction,combined with computer simulation and soil tank test,the influence of track shoe structure parameters on sand thrust(traction force per unit vehicle weight hook)was studied,which provided a basis for the development of sand spraying operation machinery.The main research contents of this paper are as follows:(1)According to the requirements of the project and the characteristics of the sand operation,the overall design requirements of the chassis were determined;according to the track design method,the basic parameters of the track were calculated,and the domestic J35 forest tracked chassis were selected as the basis;the key components of the J35 tracked chassis were reformed and designed.(2)According to the sand sieve analysis test,water content measurement test and direct shear test,the mechanical properties of the test sand were obtained.The sand thrust mathematical model of single track shoe was deduced based on Bekker subsidence theory,Janosi shear model and Rankine passive earth pressure theory,which provided a theoretical basis for the study of track shoe optimization model and walking characteristics.The simulation model of track shoe-sand interaction was established in ABAQUS software,and the influence of track shoe structure parameters on sand thrust was studied by the orthogonal test method.Based on the bionics theory,to explore the mechanism of ostrich foot travelling on sand,a sand track shoe was designed and developed,and related soil tank tests were carried out.Both the simulation and test results show that the width of the track shoe and the height of the track grouser are the significant factors that affect the thrust of the sand.(3)The improvement of the hook traction per unit weight was set as the optimization goal,the track shoe structure parameters were set as the optimized variables,the maximum power and the non-negative traction force were set as the constraints,so the track shoe optimization model was established.The parameters that can obtain the maximum hook traction force are,the track shoe width is 620 mm,the track grouser height is 83 mm,the track grousers angle is 15°,and the track grouser thickness is 8mm.Compared with the original J35 track shoe,the optimized track shoe can increase the hook traction per unit weight of 34.8%;compared to the reference track shoe,the optimized track shoe can increase the traction force of the hook per unit weight by 15.5%.(4)The Recur Dyn software was used to complete the modeling of the sand operation chassis,and the simulation of the chassis’ s straight running,turning and climbing conditions was completed on the sandy roads with different slopes.The sand spraying chassis prototype was used to conduct sand traction tests and climbing test.Simulations and tests show that the newly designed sand spraying chassis can run normally on soft and steep sand in the test area.After optimizing the track shoes,the maximum traction of the chassis can reach 36 k N,which is 30% higher than the original J35 track chassis.It can drive at a constant speed on a slope with a maximum slope angle of 30°.And no obvious slipping occurs during the driving process.At the same time,the newly designed track shoe has the effect of accumulating sand,which can reduce the degree of damage to the ground.In summary,according to the requirements of sand spraying machinery,this research combines bionics and computer simulation technology to carry out the sand running performance of the tracked chassis,the mechanism of the track shoe-sand interaction,computer simulation,and sand related experimental research.The results are of great significance for enhancing the operating quality and passing capacity of tracked machinery in sandy environments,and for promoting the development of modernization of sandy operating machinery.