金属层合板件激光协调弯曲机理及其成形规律研究

A new corrugated bulkhead is made of metal-materilas laminates. The metal-materials laminates have joint surfaces with different materials. They possess abruptly changed physical, mechanics and mechanical properties along the thickness direction. These characteristics lead to poor quality,or failures in laser bending and have impeded the competitiveness and application of high performance laminates in high-end equipments such as flying machine, deep-sea scuba machine. Therefore, this project is to develop a techniology to make laser bending of such materials entirely possible for launching capacity promotion through the investigation and understanding of laser energy input, heat transfer and stress-strain states generated by the thermal load. The overall aims are for abrupt-changed curbing in laser bending of the laminates and restraint local effect of crisping, cracking and propagation failures according to energy mode controling. The project focuses further on the study of a conforming principle and illustrates what laser energy mode gives full characteristics and regularities to the laminate bending. The restraint method is proposed for laser bending of the laminates without stress-strain changes abruptly. It keeps the metal-materials laminates bent by the conforming principle. Then, the mathematical models are developed for calculating shearing and fracture between the joint surfaces when laser energy inputs and transferes into the laminates. The laser bending theory and metallography analysis are thus improved for metal-materials laminate bending in case of the laminate cracking failure. The research achievements will enrich laminate bending theory and promote metal-materials laminate applications, which is more valuable for improving mechnical properties of the corrugated bulkhead, and promoting high-end carrier capacity.

由金属层合板制成的槽型舱壁件决定着高端运载器的性能和安全。这种复合板具有不同材料面结合和沿板厚方向材料、力学和机械性质存在突变的特征，容易失效，限制了飞行器、深水潜水器等装备的运载能力。针对金属层合板激光弯曲成形中的突变特性，研究激光能量在层合板结合面间的输入和传递规律，控制其热载荷作用，抑制层合板激光弯曲时内部应力突变，防止结合面局部起皱、起裂、扩展和剥落等失效。重点研究槽型舱壁件激光协调弯曲机理，阐述层合板激光弯曲成形的协调性和规律，形成热载荷在结合面产生应力突变的抑制方法，提高激光弯曲成形精度和质量。以层合板弯曲试验及其组织表征为依据，建立可描述多组元激光能量输入、传递数学模型及弯曲损伤模型，计算激光弯曲时结合面间剪切力，防范层合板弯曲失效，形成金属层合板激光协调弯曲理论及成形规范。研究成果对丰富层合板加热弯曲成形理论，促进金属层合板在高端运载器上广泛应用具有重要科学意义和应用价值。

1 项目简介.新型槽型舱壁件由金属层合板制成，这种复合板具有不同材料面结合和沿板厚方向材料、力学和机械性质存在突变的特征，限制了飞行器、深水潜水器等高端装备的运载能力。通过研究激光能量在层合板结合面间的输入和传递规律，控制其热载荷作用，抑制层合板激光弯曲时内部应力突变。重点研究槽型舱壁件激光协调弯曲机理和规律，形成热载荷在结合面产生应力突变的抑制方法。研究结果用于飞行器、潜水器等高端装备中的新槽型舱壁件成形，试制出两种舱壁比例样件。.2 主要创新点及其主要研究进展. （1）模型建立和数值模拟。采用不同材料参数修正方法，建立含结合面的层合板脉冲激光弯曲有限元模型，分析不锈钢/碳钢层及其结合面的温度场、应力应变场的分布情况，进行层合板激光协调弯曲机理研究。提高金属层合板激光弯曲数值模拟精度15%左右，试验验证计算结果可靠。. （2）弯折区组织增厚现象和机理。借助图像处理软件测量各层厚度及碳钢层晶粒尺寸。层合板在激光作用下，材料组织晶粒尺寸增大，上界面处晶粒挤压变形，不锈钢层合板在加热阶段“热膨胀增厚”及冷却阶段“挤压增厚”的共同作用，使层合板激光弯折区厚度增加。. （3）弯曲角度预测与协调弯曲机理。由于结合面过渡层，在有限元分析中，缺少过渡层的弹性模量、屈服强度等计算参数。采用金相显微镜等检测仪器对激光弯折区的元素扩散进行表征；得过渡层附近弹性模量分布，用于修正层合板激光弯曲角度数学模型中结合面参数，提高弯曲角度预测精度5%。.（4）成形规律与典型件试制。基于扫描线上温度均匀分布的思想，提出一种局部扫描校正方法，经实验验证翘曲线弦高从0.24mm降低到0.09mm。得到弯曲角35°-55°的直线槽比例样件。 .3 研究成果. （1）在国內外期刊发表论文21篇，A类英文期刊5篇，中文期刊13篇，国际会议3篇，SCI收录5篇，EI收录16篇。（2）获国家授权发明专利2项，获美国授权发明专利1项，申请美国、欧盟专利2项。（3）培养已毕业研究生7人。