Research On Local Stress Of Telescopic Crane Boom Sliding Block

With the rapid development of economy and society,there are more and more project construction projects,and the rapid lifting of cranes is becoming more and more obvious in engineering construction.The telescopic boom crane is widely used due to its low occupancy and high efficiency.The telescopic boom is usually made of box type structure,which is composed of multiple boxes type arm joints.The sliding block is provided between the adjacent arms sections to ensure the stretching friction and load transfer between the arms.as the lifting performance improvement and boom length increases,telescopic box boom local stability of the sliding block contact problem increasingly prominent.To deals with the calculation of local stress in the contact part of the box telescopic boom.the theoretical analysis and experimental method are carried out.In this paper,we carried out the material test for the high strength steel and the special cast nylon slide material,and the stress-strain relation curve was obtained through the material test.The mechanical properties of imported high-strength steel and domestic high-strength steel were analyzed,and the relevant mechanical parameters were obtained.The friction test of the high strength steel material and the slide block nylon material was carried out,analysis the main factors affecting the coefficient of friction and its change law,establishing database of the friction coefficient between different materials,local stress analysis of the theory for the slider effect position to provide basic data.Taking an automobile crane boom as the test subject,the contact pressure between the slider and the boom face is obtained through the pressure distribution measurement system under multiple load conditions,and the local stress of the boom and slider is obtained by the contact strain gage.The test results,which can be used to measure the deflection of arm and study the static stiffness characteristics of the boom.Using non-linear finite element contact analysis technology,a theoretically designed boom and slider contact analysis model corresponding to the test model is established.The local stress distribution of the boom body at the action of the slide under multiple working conditions is obtained,and it is performed with the test data.In this paper,the influencing factors of the local stress in the contact position of the boom and the slider are further studied in detail.Monte Carlo method is used to study the contact reliability of the boom slider.Provides the theoretical basis for the structural design and improvement of the box-type telescopic boom.