CAJ | 학술논문

双脊矩形管在其绕弯成形过程中极易出现截面变形等缺陷，严重制约了其成形质量及成形极限的提高。管材的截面变形主要由各阶段的应力状态决定，研究管材应力变化规律有助于提高对绕弯变形机理的认识，进而为减少截面变形策略的制定提供指导。运用ABAQUS／Explicit软件，建立了双脊矩形管绕弯成形三维有限元模型，并通过实验验证了该模型的可靠性。基于该模型，将双脊矩形管弯曲部分分为芯模支撑区和无芯模支撑区2个区域，分别研究了双脊矩形管绕弯成形过程中内外腹板及内外脊槽对称线上的特征点 B1、B2、B3、B4的等效应力、切向应力和周向应力在2个区域的变化规律。研究结果表明：当截面位于芯模支撑区时，该截面内外腹板对称线上的点 B1、B2上的等效应力、切向应力及周向应力均出现不同程度的波动，内外脊槽对称线上的点 B3、B4上的应力值没有出现明显的波动现象，但 B3上的切向应力、周向应力出现反向加载现象；当截面位于无芯模支撑区时，应力变化比较平缓。
쌍척구형관재기요만성형과정중겁역출현절면변형등결함，엄중제약료기성형질량급성형겁한적제고。관재적절면변형주요유각계단적응력상태결정，연구관재응력변화규률유조우제고대요만변형궤리적인식，진이위감소절면변형책략적제정제공지도。운용ABAQUS／Explicit연건，건립료쌍척구형관요만성형삼유유한원모형，병통과실험험증료해모형적가고성。기우해모형，장쌍척구형관만곡부분분위심모지탱구화무심모지탱구2개구역，분별연구료쌍척구형관요만성형과정중내외복판급내외척조대칭선상적특정점 B1、B2、B3、B4적등효응력、절향응력화주향응력재2개구역적변화규률。연구결과표명：당절면위우심모지탱구시，해절면내외복판대칭선상적점 B1、B2상적등효응력、절향응력급주향응력균출현불동정도적파동，내외척조대칭선상적점 B3、B4상적응력치몰유출현명현적파동현상，단 B3상적절향응력、주향응력출현반향가재현상；당절면위우무심모지탱구시，응력변화비교평완。
The cross sectional deformation of DRRTs occurs easily in rotary draw bending ,which largely restricts the improve‐ment of bending quality and forming limit .The cross sectional deformation of a tube enormously depends on its stress state ,so it is benefit to enhance the knowledge of deformation mechanism by studying the stress variation and then it is helpfnl to develop method for decreasing cross sectional deformation .Based on the platform of ABAQUS/Explicit ,a three‐dimensional finite ele‐ment model of DRRT in rotary draw bending was established and its reliability was validated by experiment .Dividing the bended portion of DRRT into two zones ,MSZ(mandrel support zone) and NMSZ(no mandrel support zone) ,variation laws of equivalent stress ,tangent stress and circumferential stress at the feature points B1‐B4 on the symmetric lines of flanges and ridge grooves of DRRT were studied with the aid of this model .The results show that when the section is located in the MSZ ,the equivalent stress ,tangent stress and circumferential stress of B1 and B2 fluctuate on different levels .The similar phenomenon does not occur for the stresses of B3 and B4 ,but the tangent stress and circumferential stress of B3 generate reverse loading phenomenon .When the section lies in the NMSZ ,the stresses change gently .