Study On Web Stability Of Overhead Crane Based On Finite Element

Overhead crane is widely used in machining,repair,assembly workshop or warehouse and other occasions.It is the most widely used,the largest number of a kind of lifting machinery,production and manufacturing,warehousing logistics and other fields have a vital role.The main girder is the most important bearing member,which is the key to the whole machine structure.In view of the lack of stress analysis of the internal structure of the main girder in the traditional theory,a more conservative way is generally adopted for structural design.Therefore,the research on the main girder structure has very important practical significance.The research object of this paper is the box girder structure of overhead crane and its web lattice with stiffening ribs.The buckling instability of box girder and ribbed web of overhead crane is studied as follows.Firstly,the stability of the girder model of the overhead crane is analyzed.The number of diaphragms inside the main girder is changed and the critical load coefficient of the main girder is observed according to the buckling mode.It is found that the stability of the main girder of overhead crane can be improved by adding a finite number of diaphragms within the requirements of the code,and when the number of diaphragms is greater than 19,the stability of the main girder can be improved greatly by decreasing the spacing of diaphragms.Then,by changing the aspect ratio of the web,the critical load coefficient and displacement under different aspect ratio were analyzed,and the local stability of the web was studied.The results show that the smaller the aspect ratio of web lattice,the stronger the local stability of web,and when the aspect ratio of web lattice decreases to 0.9,the further reduction of diaphragm spacing will improve the local stability of web.Secondly,the stability strengthening effects of L,rectangular and T stiffeners with the same height and cross-sectional area on the web were explored respectively.The results show that the strengthening effects of L-shaped ribs are more than T-shaped ribs than rectangular ribs.The strengthening effects of L-shaped ribs and T-shaped ribs are obviously higher than those of rectangular ribs.The difference of stability strengthening between L rib,T rib and rectangular rib increases with the decrease of length-width ratio.Thirdly,the relationship between the stability of web and the width of longitudinal stiffener is explored.The results show that the local stability of the web can be improved by increasing the rib section width regardless of the length to width ratio of the web area in the specification.With the gradual increase of rib section width,its ability to strengthen the stability of the web area will be weakened.Finally,the optimum distance between the longitudinal stiffener and the upper flange plate in the web grid with different aspect ratios is explored and compared with the specification.The correctness of the specification is verified by simulation.The results show that when the ratio of length to width is small,the most suitable position of longitudinal stiffener is close to the smaller height in the interval.When the ratio of length to width is large,the most suitable position of the longitudinal stiffener is close to the larger height in the interval.