Abstract:Elastic deformation has always been a key factor restricting the machining quality in thin walled machining. In order to solve this problem， a method for the prediction and compensation of elastic deformation is investigated in this study. Firstly， based on the finite element method， a layered milling model is built for the straight micro-thin wall with different thicknesses. The deformation law of the thin wall along the direction of height and length is studied. A thin wall deformation model with the cantilever beam method is establishedby considering the effect of material removal on the stiffness of the thinwall. Secondly， a single degree of freedom cutting force measurement and real-time cutting parameter compensation device is developed. The thin wall deformation is estimated based on the cutting force and deformation model measured in real-time during the thin wall cutting process. The deformation prediction is used for the compensation value to compensate for the radial cutting parameters in real-time. At last， a comparative experiment is conducted. The results show that the average relative error of the thin wall decreases from 6.86% to 2.19% after the radial cutting parameter compensation， which verifies the model reliability and the effectiveness of the compensation device.

Abstract:Using initial parameter solutions and transfer matrix method，the finite element formulation for restrained torsion of a thin-walled box girder was presented. The equivalent nodal forces of distributing torque and bimoment acted on an element were also derived. Based on the displacement solutions of the finite element method for restrained torsion, a new algorithm for calculating the flexural-torsional moment was developed. The relevant stiffness matrix and fixed-end forces for distributing torque and bimoment acted on the element were established. It facilitated the calculation of normal stress and shear stress. The examples show that the calculation results of the proposed method agree well with the theoretical solutions, which proves that the stiffnesses for restrained torsion, equivalent nodal forces for distributing torque and bimoment acted on element as well as new algorithm for flexural-torsional moment are exact.

Abstract:The bending of a new typical gas holder under gas pressure is crucial to ensure the normal operation of the structure. It can be simplified to elastic bending of ring stiffened cylindrical shell, which is under partial internal pressure and has multiple circular reinforced ribs. Stripe Beam on Elastic Foundation Method (SBEFM) was extendable to the structure system. At the same time, traditional discrete stiffened method (TDSM) was improved. A gas holder of 300 000 m3 was taken as an example for analysis. On this basis, the method judging ring stiffened cylindrical shell smeared or discrete was presented. The new analysis shows that SBEFM has a wider applicability, higher accuracy and better efficiency than other methods and the improved discrete stiffened method is effective when the ring spacing is greater than 3.875 (Rh)1/2.

Abstract:A semi-energy method is used to analyse the elastic buckling behaviourof typical edge-stiffened plates.The solutions obtained have revealed the three kinds ofbuckling modes and characteristics,which are valuable for engineering practice.

Abstract:A semi-energy method to analyse the buckling behaviour of edge-stiffened plates under combined compression and bending is presented in this paper, One unloaded edge of the plate is restrained elastically against rotation and the other is stiffened by a st