【作者】 贺龙；

【导师】 张如华；

【作者基本信息】 南昌大学 ， 材料加工工程， 2010， 硕士

【摘要】 劈挤是一种新近命名的尚处于研究和探索阶段的局部连续塑性成形方法。本文以槽深为10mm、槽底宽为12mm的燕尾槽作为研究对象,借助数值模拟和物理模拟方法,研究了燕尾槽劈楔劈挤变形过程,初步归纳了其成形规律。论文的主要工作以及取得的成果有如下几个方面：(1)提出了燕尾槽劈挤成形的研究方案,确定了以劈分角(α)、劈入角(β)、燕尾角(θ)为劈挤主要影响因素以及主要成形指标稳态变形时的最大成形力(P)、槽侧隆起高度(H)和隆起影响宽度(B)、劈入塌角(A)、不稳定隆起长度(L)以及废料相对槽截面长度(△L)。通过交互试验验证了α与β二者不存在交互性后,利用正交试验法进行合理安排16组试验。(2)利用有限元模拟软件Deform-3D对燕尾槽劈挤成形过程进行了模拟研究,分别对劈挤成形过程中行程-载荷曲线、等效应力应变分布、追踪点位移曲线等进行了详细分析,并以行程-载荷曲线与模拟效果图相结合的形式将劈挤成形过程分为劈楔劈入、稳态变形、劈楔推出废料3阶段；研究表明,燕尾槽劈挤变形区包括劈入塌角、前方堆积、槽侧隆起、槽底受压等。(3)借助正交设计软件(正交设计助手ⅡV3.1)对模拟试验结果进行方差分析,结果表明：影响P的因素主次顺序为θ、α和β；影响H和B的因素主次顺序为β、θ和α；影响A的主要因素为β；影响L的因素主次顺序为θ、β和α；影响△L的主要因素为θ；绘制了各因素对指标的影响曲线。设计制造了6组试验模具,利用铅材料进行了物理试验,并追加数值模拟试验,比较分析得到,物理试验结果与数值试验结果基本吻合。(4)分析了燕尾槽劈挤成形出现槽口张开和槽侧隆起缺陷的原因。就槽口张开现象提出了2个改善方案,设置固定槽口滞后角β0和自动生成可变β0；就槽侧隆起现象提出了逆向求解设计思想,设计了一种坯料预成形形状；通过数值模拟试验得到验证。更多还原

【Abstract】 Splitting extrusion, a newly named local continuous plastic forming method, is still on the way of research and exploration.In this paper, by taking the dovetail slot as the research object, the slot depth is 10mm and the slot bottom width is 12mm in the study. The splitting extrusion deformation process of the dovetail slot was researched and forming laws was concluded preliminary in the article, using numerical simulation and physical simulation.The main research work and results are as follows:(1)The research scheme of dovetail slot splitting extrusion forming was proposed. The main factors including splitter broadening angle, splitter tilt angle, and dovetail angle were determined, and the main indicators including the stable deformation maximum force P, slot-side swelling height H and its influence width B, sunk angle of wedging A, unstable swelling length L, relative section length of the waste△L were determined. The 16 tests were arranged reasonably using orthogonal test method after verifying no interaction betweenαandβby interactive test.(2) Using finite element simulation software Deform-3D, the dovetail slot splitting extrusion forming process was simulated and researched. The process of splitting extrusion stroke-load curve of stress-effective and strain-effective distribu-tion, the displacement curve of tracking points were analyzed in detail. Splitting extrusion forming process were divided into 3 stages, the first is dedicated to wedging into, the second concentrates on steady deformation and the third is waste material extruded, by combining stroke-load curve and simulation graph. The research results show that forming area includes four aspects:a) sunk angle of wedging; b) front metal accumulation; c) slot-side swelling and d) pressure of slot bottom.(3)Using orthogonal design software(orthogonal design assistantⅡV3.1), variance analysis of simulation results show that, the primary and secondary relationship among every factors on indicator P isθ,αandβ;and on H and B isβ,θandα; and on L and B isθ,βandα; the main factor on indicator A isβ, and on△L isθ. Meanwhile, relationship curves between factors and indicators were drawn.6 tests dies were designed and made, and physical tests were finished by Lead, and numerical tests also were added, the compared analysis results show that the two coincides basically.(4) The reasons of forming defects (such as slot opening and slot-side swelling, etc.) of dovetail slot splitting extrusion were analyzed. Two improving schemes on slot opening phenomenon were proposed:a) setting a fixed notch lag angleβ0 and b) automatically generating a variable Po.Reverse design thought about slot-side swelling phenomenon was put forward, and a kind of blank performing shape was designed. All were verified by numerical simulation.更多还原