船舶横梁纵桁腹板开孔应力集中计算

本文将解析分析与有限元数值分析相结合,研究了船舶纵桁和横梁腹板上开圆孔和腰圆孔后的应力集中问题,建立了用于梁结构应力集中的局部应力分析法。获得了:(1)开孔直径在1/10～1/2腹板高度变化范围、开孔位置可沿梁长度方向变化的孔口应力集中简便计算公式;(2)上述孔用不同厚度板加强或用围壁加强后的应力集中简便计算公式;(3)在研究了两个孔靠近后对孔口应力分布的影响后,提出了梁上开多孔时的应力集中计算方法。本文方法计算结果分别与光弹性试验、大型钢模试验结果和有限元法对整体梁的计算结果作了比较,表明本文方法可靠而方便。

METHOD TO DETERMINE STRESS CONCENTRATION IN SHIP I-BEAMS WITH OPENINGS

Stress concentration around circular opening and also rectangle-circu-lar opening (holes are cut in long strip with circular shape at both ends)at the web of ship I-beams or girders are investigated.Combining conve-ntional theory of beam analysis with the finite element method,a localizedstress analysis method is proposed.Main results obtained are as follows:1.Shearing forces have most considerable effect in stress concentrati-on than other loading condition,size and shape of hole than other geome-trical factors of the beam.2.Simple formulas for stress concentration are presented,when theabove holes are strengthened by additional strengthening plate or by addi-tional strengthening rings with various thicknesses.3.Stress distribution affected by two nearby holes of ship I-beamsare studied.Methods for determining stress concentration around multipleholes along the length of beam are also presented.Stress calculated by the simple formulas in this paper is compared forthe whole beam with the results from photoelastic and steel model,expe-riments,and also with the FEM calculations using program SAP.It hasbeen verified that the method for defermining stress concentration in shipI-beams with opening presented in this paper is reliable and also very si-mple to apply.