首页|振动辅助Ti-45Nb钛合金冷镦成形有限元模拟研究

振动辅助Ti-45Nb钛合金冷镦成形有限元模拟研究

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在金属塑性成形加工中,振动辅助成形技术的应用可以有效地降低零件成形载荷,提高产品质量.本文首次基于塑性大变形理论和有限元数值模拟,对Ti-45Nb钛合金振动辅助冷镦成形机理进行了分析与研究.首先以位错密度的变化作为内变量描述材料在变形过程中材料软化、硬化等关系,建立了振动辅助冷镦成形本构模型,并采用MATLAB工具编程拟合出本构方程中的材料参数.然后利用Deform有限元软件对Ti-45Nb钛合金的大长径比薄壁零件进行建模仿真分析,根据反挤压道次中材料成形流动情况的结果,对模具中应力集中的凸模结构进行优化设计.结果表明:本文基于大变形建立的本构模型能够有效描述振动的软化作用,尤其在材料塑性变形阶段拟合较好,预测精度评估相对系数(RC)值＞0.994.此外,通过建模仿真分析得出的多级倒角结构可有效促进材料流动,减小模具磨损,提高模具寿命.
Study on finite element simulation of vibration assisted Ti-45Nb titanium alloy cold heading forming
The application of vibration assisted forming technology in metal plastic forming can effectively reduce the forming load of parts and improve product quality.Based on the theory of large plastic deformation and finite element numerical calculation,the mechanism of vibration assisted cold heading forming of Ti-45Nb titanium alloy is firstly analyzed and studied in this paper.Firstly,the change of dislocation density is taken as the internal variable to describe phenomenally strain hardening,soft etc,and the vibration-assisted cold heading constitutive model is established.The parameters of the proposed visco-elasto-plastic constitutive model are fitted by MATLAB.Secondly,the finite element software Deform is employed to simulate the thin-walled parts made of Ti-45Nb titanium alloy with large aspect ratio.From the perspective of material flow,the design of the punch structure with stress concentration is optimized in the die.The results show that,the constitutive model based on large deformation can effectively describe the softening effect of vibration,especially in the plastic deformation stage of materials and relative coefficient of prediction accuracy evaluation value＞0.994.In addition,through modeling and simulation analysis,it is concluded that multi-level chamfer structure can effectively promote material flow,reduce mold wear and improve mold life.

large length-diameter ratiobackward extrusionvibration assistedcold headingfinite element simulationdie designconstitutive modeldislocation density

林凯、杨李杰、王英、陈兴、胡鹏科

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宁波大学机械工程与力学学院,浙江宁波 315211

浙江省零件轧制成形技术研究重点实验室,浙江宁波 315211

大长径比 反挤压 振动辅助 冷镦成形 有限元模拟 模具设计 本构模型 位错密度

浙江省自然科学基金重点项目宁波市重大科技攻关暨揭榜挂帅项目科研创新基金项目

LZ22E0500022022Z009IF2021030

2024

10.11951/j.issn.1005-0299.20220420

材料科学与工艺
中国材料研究学会 哈尔滨工业大学

材料科学与工艺

CSTPCD北大核心
影响因子：0.491
ISSN：1005-0299
年,卷(期)：2024.32(4)