Modified Equivalent Load Method for Welding Distortion Analysis

In this study, modified equivalent load method for welding distortion analysis is suggested to improve its accuracy. To avoid the excessive computational time for welding distortion analysis of large welded structures, shell element-based elastic analysis methods are widely used, applying the inherent deformation approach. Equivalent nodal forces are commonly used in common FE (Finite Element) codes to enter these inherent deformation values. However, the conventional method cannot estimate precise longitudinal bending following the conventional equation. In this study, the problem of the existing equivalent load method is analyzed by a case study, and the modified equivalent load method that can estimate angular distortion, transverse shrinkage, and longitudinal bending is presented based on the FEM principle. The results show that by applying the proposed method, the shell element-based elastic FE approach for the welding distortion analysis can be achieved with improved accuracy.

Anchor Spacing Design of Pre-Stressed Tunnel Concrete Lining with Un-Bonded Annular Anchors for Songhua River Water Supply Project

At present, annular anchor pre-stressed tunnel Concrete lining is the main design method of poor -quality surrounding rocks, thin covering and high internal water pressure tunnel. Based on the contact of tendons and concrete, the annular anchor lining can be classified into bonded and un-bonded. Cable spacing is one of the key parameters in the design of the un-bonded annular anchors pre-stressed concrete lining. The optimal anchor spacing can not only meet the demand of the project, but also save the cost of construction. In this paper, the anchor spacing is studied in the design of pre-stressed tunnel concrete lining with un-bonded annular anchors for Songhua River water supply project. The equivalent load method and solid modeling method are combined in Flac3d 3D modeling. Numerical simulation of pre-stressed effects for different anchor spacing in tension and operation of the concrete lining were analyzed. The optimal anchor cable spacing is received, which is a reference for the design and construction of similar projects in the future.

The Numerical Research on the Jumping Induced by the Uniform and Non-Uniform Ice-Shedding of Transmission Lines

This paper introduces several kinds of icing and ice-off simulation method: the equivalent load method, quality method, Támás model method and cell death method. With a large span cross section as an example, using finite element method, established the finite element model of single span icing wire, analyzed the non-uniform ice-off and the even ice-off,the results show that: Non-uniform ice-off dynamic tension is significantly smaller than even ice-off dynamic tension,the smallest dynamic tension is closely related to wire jump amplitude, the greater jump amplitude leads to the smaller dynamic tension,the essence of which is determined by the conductor slack.