(哈爾濱工業(yè)大學 材料科學與工程學院, 哈爾濱 150001)
摘 要: 采用實驗和數(shù)值模擬研究5A02鋁合金薄壁管材充液壓彎成形過程中內(nèi)壓對缺陷的影響規(guī)律，分析內(nèi)壓對彎曲內(nèi)側(cè)起皺、截面畸變及壁厚分布的影響，獲得壁厚變化規(guī)律；通過數(shù)值模擬給出的應(yīng)力狀態(tài)，揭示缺陷形成機制。結(jié)果表明：提高內(nèi)壓能降低軸向壓應(yīng)力的絕對值，減小失穩(wěn)起皺趨勢，當內(nèi)壓超過一個臨界值時，皺紋完全消除。對于直徑為63 mm、壁厚為1 mm的5A02-O鋁合金管材，其內(nèi)壓臨界值為2.8 MPa。充液有效地減小截面畸變程度，隨內(nèi)壓的增大，截面畸變程度逐漸減小。彎曲后，壁厚最大減薄點位于彎曲外側(cè)點，且隨內(nèi)壓的增大，軸向和環(huán)向拉應(yīng)力均呈增大趨勢, 彎曲外側(cè)壁厚度減薄的趨勢也增大。
關(guān)鍵字: 內(nèi)壓；薄壁管；鋁合金；充液壓彎；起皺
thin-walled aluminum alloy tube
（School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:The influence of internal pressure on faults was investigated for a 5A02 aluminum alloy thin-walled tube in hydro-bending process by experiment and finite element method. The effects of internal pressure on wrinkling on the inner arc, cross-section distortion and wall thickness distribution were analyzed, and the thickness variation regularity was achieved. The mechanism of defect was revealed through stress state given by numerical simulation. The results show that the absolute value of axial compressive stress can be reduced by improving the internal pressure, and the wrinkling tendency declines. The wrinkles can be completely eliminated while the internal pressure reaches a critical value, and the critical value is 2.8 MPa for a 5A02-O aluminum alloy tube with an outer diameter of 63 mm and a wall thickness of 1 mm. The cross-section distortion decreases with the internal pressure increasing. The biggest thickness thinning of the specimen appears at the bottom of the outer arc. The axial stress and hoop stress enhance as the internal pressure rises, and the tendency of thickness thinning on the outer arc increases.
Key words: internal pressure; thin-walled tube; aluminum alloy; hydro-bending; wrinkling
