Mechanism And Experimental Study Of Vibration Digging

The rapid development and progress observed in a wide range of areas in today’s society has promoted a wide application of all types of engineering machines/equipment such as hydraulic excavators in many different fields.However,more and more challenges are being faced each and every day.For example,most of the currently existing hydraulic excavators have many challenges not to mention large resistance,low efficiency and large fuel consumption when dealing with complex operation.Moreover,these machines have great losses in components including bucket teeth among others.Therefore,with the continuously depleting global energy resources,it is urgent to find a more suitable way of mining,aiming at reducing the digging resistance and energy consumption,and hence,making the hydraulic excavators more suitable for social development purposes.The use of vibration technology in hydraulic excavators,in order to push the bucket into the soil using vibration effect in the process of mining,makes the soil under the effect of oscillation structure changes,which then reduces the digging resistance of bucket and improves the ground breaking ability and hence reducing energy consumption.This obviously has a tremendous important significance in promoting the development of hydraulic excavators.Therefore,the application of vibration excavating of hydraulic excavator is studied in this paper.Starting from the soil properties,the change of soil shear strength under vibration is analyzed,and the mechanism of vibration excavation and drag reduction is obtained.According to the vibration excavating function,the whole vibration excavation test platform is needed.Also,the vibration excavation test is carried out to verify the feasibility of the drag reduction theory and the test platform,and the influence of the change of the vibration parameters on the excavation resistance is obtained.The research is carried out focusing on the following aspects:(1)The basic properties of soil are analyzed,and the relationships between the soil stress,the shear strength as well as the critical state of soil damage are obtained.(2)An analysis of the dynamic constitutive relation and dynamic property of soil is first performed,then the influence of vibration parameters on the dynamic strength of soil is obtained and finally the effect of excavation on resistance is presented.Moreover,according to the theory of soil shear strength,the mechanism of drag reduction is analyzed.As a result,the shear strength of soil will be decreased under the action of vibration excavation and then the decline of digging resistance will be made.(3)To analyze the feasibility of vibration excavation,we increase the vibration of bucket by installing the vibrating oil cylinder independently and developing the corresponding vibration excitation device and hydraulic system,so that the bucket can achieve different parameters of the vibration excavation effect.(4)The hardware and software of the control system of the vibration mining platform are developed and a lot of intelligent control functions such as vibration output,parameter change control,data detection,processing and preservation,human-machine interface control are developed.(5)The vibration and excavation tests of sand and loess are carried out to verify the effectiveness of vibration excavation and drag reduction,and the change rules of mining resistance under the change of vibration parameters(frequency,amplitude and mining speed)are analyzed.The response surface analysis method is used to obtain the influence of the vibration parameters and the interaction between the parameters on the excavation resistance,and the optimum vibration parameters of the two kinds of soil are optimized.Through theoretical analysis of soil shear strength,vibration can reduce the shear strength of soil,that is,in theory;we can reduce excavation resistance by means of vibration excavation.At the same time,after the vibration excavation test,we can easily get the vibration mining test platform.This helps us to achieve all the requirements in both the vibration excavation and the reduction of the digging resistance and which establishes the relationship between the vibration parameters and the digging resistance.This research will help to promote the application and development of greater vibration in hydraulic excavator,so that the hydraulic excavators can be more reliable and suitably address to the ongoing social development needs.