铝管锥形模机械扩径变形区壁厚分布规律

研究了管材锥形模机械扩径变形区应力分布的特点,根据应力-应变关系,分析了变形区壁厚可能存在的分布规律,通过求解变形区应力分布,根据全量理论和体积不变原则,提出了变形区壁厚分布的解析式,基于该公式,分析了扩径系数和摩擦系数对壁厚分布的影响,结果表明,扩径系数较小时,摩擦系数对壁厚分布影响较小,变形区壁厚均减薄;当扩径系数较大时,变形区存在壁厚分界面,分界面之前(靠近模具前端)壁厚增厚,分界面之后壁厚减薄,并且摩擦系数越大,分界面半径越大。进一步数值模拟证明,该壁厚分布公式正确。

Thickness distribution at the deforming zone of aluminum tube in mechanical expanding

Stress distribution characteristic of deformation zone in tube mechanical expanding is investigated.The possible pattern of thickness distribution at the deforming zone is analyzed according to the stress-strain relationship and analytic formula of thickness distribution at the deforming zone is derived according to total strain theory and volume constancy.Based on the analytic formula,the effects of the expanding coefficient and the friction coefficient on the thickness distribution are analyzed.The analytic results indicate that with smaller expanding coefficient,the effect of the friction coefficient on thickness distribution is lesser and the thickness of the deforming zone is reduced.When the expanding coefficient is getting larger,there would be a thickness interface at the deforming zone with thickening in front of the interface (near front end of die) and reduction behind the interface.The radius of the interface would increase with the increase of friction coefficient.The validity of the thickness deformation formula has been proved by further numerical simulation.