固定管板釜式重沸器斜锥壳转角过渡区的应力分析

STRESS ANALYSIS OF KNUCKLE REGIONS IN SLANT CONICAL SHELL OF FIXED TUBESHEET RE-BOILER

利用 FEPG 软件的前处理程序生成系统 MTI,对固定管板釜式重沸器的斜锥壳建立了简化力学模型,并进行了有限元分析计算,发现斜锥大小端过渡区均存在应力集中现象,其中大端转角过渡区经线方向存在明显的弯曲应力,内壁表现为拉应力,外壁表现为压应力;环向内、外壁均存在明显的拉应力,且与最大拉应力位置相对应的外、内壁上亦存在一定的压应力。对一系列参数的斜锥壳进行了计算,整理了斜锥大小端过渡区在各计算参数下基于分析设计的应力集中系数,发现无论大端还是小端,应力集中系数随大小端直径比的增大、斜锥角的增大而增大;一次加二次应力的应力集中系数总是大端过渡区较大,而局部薄膜应力的应力集中系数当大小端直径之比较小时,小端较大,当大小端直径之比较大时,大端较大。

MTI System derived from preprocess- ing program of PEPC software was used to es- tablish a simplified mechanics model for the slant conical shell of fixed tube-sheet reboiler and a stress analysis was made with finite ele- ment method.It was found that the stress con- centrated at both small and big side of the slant conical of transition knuckle regions,while the meridian of the big end having obvious bending stress(tension stress at inside and compressive stress at outside)and circumferential tension stress(at the opposite side where it occurs there is a relatively smaller compressive stress)occurs at the knuckle region of the big side.The SCFs (Stress Concentration Factors)based on analyti- cal design were working out with parametric a- nalysis,and SCF curves were given out.It is found that the stress concentration factors of the big and small side is varied with the various di- ameter ratio and enlargement of the slant conical of small and big side.The stress concentration factors(SCF)of primary and secondary stress is always higher in knuckle region,while when small and big side has small diameter ratio in lo- cal SCF of primary stress,the size of small side is big,and when the diameter ratio is big at the small and big sides,the size of big side is big.