异型非均质磁流变弹性软模调控下复杂板件多区域变形协调性的控制及其作用机理

Aiming at the common problems in the forming of complex sheet components, such as the drastically different stress states in each region of sheet, the incompatible material flow, and the difficult process control, this project proposes a novel idea to regionally and periodically control sheet forming by using irregular-shaped and nonhomogeneous magneto-rheological elastic dies. Concretely, external magnetic field and internal magnetic particles with regional distribution are utilized to adjust the regional properties of elastic dies in real time. Then a non-uniform, real-time controllable pressure field is established to control the deformation coordination of sheet in all regions. Specific to the scientific issues surrounding the distribution and variation of the pressure field of elastic die, and its regulation mechanism for multi-zone deformation of sheet metal, the finite element model of pressure forming process employing irregular-shaped and nonhomogeneous magneto-rheological elastic die will be established. The influence mechanism of local content of magnetic particles, structure parameters of elastic dies and external magnetic field strength on the spatial distribution and time-dependence of pressure field of elastic dies will be researched and revealed. Bulge tests of “non-uniform” sheet blank and forming experiments of complex-shaped components will be conducted to ascertain the compatible and matching mechanism between pressure field of elastic die and multi-region deformation of sheet. Using the 3D DIC method to dynamically track and measure the full-field deformation, then the multi-region and multi-stage compatible deformation mechanism of sheet metal will be clarified under the regulation of irregular-shaped and nonhomogeneous magneto-rheological elastic dies. The research results are expected to expand the control method and theory towards the multi-region compatible deformation of sheet, and may provide a new way for precise and intelligent forming of complex sheet components.

针对复杂板件成形中各区域应力状态差异大、材料流动不协调、过程控制困难的共性问题，本项目提出使用异型、非均质磁流变弹性软模分区域、分阶段调控板材成形的新思路，通过外磁场、内部区域化分配的磁性颗粒实现软模局部性能的实时调节，形成非均匀、实时可控的压力场，控制板材各区域变形协调性。围绕软模压力场分布、变化规律及其对板材多区域变形的调控机制等科学问题，建立异型非均质磁流变弹性软模压力成形有限元模型，研究并揭示磁性颗粒局部含量、软模结构参数、外磁场强度对软模压力场空间分布和依时演化规律的影响机制；开展“非均匀”板料胀形及复杂形状板件拉深成形实验，探明软模压力场与板材多区域变形的匹配协调机制；采用三维DIC方法动态追踪测量板材全场变形，揭示异型非均质磁流变弹性软模调控下多区域、多阶段协调变形改善板材成形性的机理。研究成果有望拓展板材多区域变形协调控制方法和理论，为复杂板件的精确、智能化成形提供新途径。

针对复杂形状或“非均匀”板料性质导致的板材零件应力状态和材料流动控制难点，提出了使用异质磁流变弹性模作为传压介质的板材成形控制策略；构筑了具有非均匀力学性能和压力响应性质的异质磁流变弹性模；确定了基于异质磁流变弹性模的板材表面差异化压力场构建、形成原理、分布和演变规律，并得到其与板材各区域应力状态、应变分布的匹配协调关系；通过对板材复杂应力状态下各区域变形的动态控制，提高了典型非对称板材构件成形性；基于外磁场下的成形实验和成形过程有限元分析结果，揭示了异质磁流变弹性软模的差异化压力场调控板材多区域协调变形，以及改善板件成形性的机理。项目取得的主要研究进展包括：（1）提出了板材异质磁流变弹性模成形新方法，掌握了基于异质磁流变弹性体的差异化压力场构建方法，确定了压力场分布和演变规律；（2）构建了差异化压力场作用下板材变形解析分析模型，开展了不同外磁场强度、不同羟基铁颗粒分布形式和含量的异质磁流变弹性模作为传压介质的板材胀形实验，归纳了异质磁流变弹性模作用下板材的非均匀变形行为特征；（3）开展了差异化压力场下的SS304/SS316拼焊板、Al6014局部热处理板胀形实验，探明了差异化压力场对此类板材变形行为的影响规律，确定了差异化压力场与此类板材各区域应力应变分布的匹配机制；（4）研制了典型非对称薄壁构件成形装置，开展了差异化压力场下的构件成形实验，探明了差异化压力场作用下此类构件多区域、多阶段变形行为特点，阐明了差异化压力场改善此类板材构件成形性的机理。项目研究成果在材料加工领域国内外重要学术期刊发表论文8篇，其中SCI收录论文7篇。获授权国家发明专利5项，培养硕士研究生3人。项目的实施为解决复杂板件各区域变形不协调、成形性低的问题提供了新思路和新途径。

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