【作者】 李玥华；

【导师】 富宏亚；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2013， 博士

【摘要】 自动纤维丝铺放技术是生产大型或超大型复杂表面形状复合材料构件的制造技术之一，属于极端制造的一种，被广泛应用于航空、航天飞行器制造领域。自动纤维丝铺放技术选取热塑性预浸丝为原料，同时引入原位固化成型技术代替以往的热压罐固化成型技术，不仅摆脱了热压罐尺寸对所加工构件大小的限制，还显著提高了生产效率、降低了生产成本。因此，热塑性预浸丝自动纤维丝铺放技术已经成为复杂表面形状复合材料构件制造的一项关键技术，得到了越来越广泛的重视。实现满足要求的复合材料构件的铺放，不仅需要相应的预浸丝材料、加工设备，还需要对自动纤维丝铺放过程中涉及的热塑性预浸丝铺放成型工艺、轨迹规划算法、铺放设备后置处理算法及铺层力学特性进行深入的研究。将热塑性预浸丝与原位固化成型技术相结合应用于自动纤维丝铺放过程中，可以同时完成复合材料构件预成型和最终固化成型，但也对铺放过程中各铺放参数的要求更加严格。因此，需要对铺放成型工艺进行研究，确定合理的铺放参数，以确保生产出符合设计指标的复合材料构件。本文对铺放成型工艺中加热工艺、冷却工艺及铺层间紧密接触度进行了研究，研究内容包括根据热塑性预浸丝（APC-2型）的物理性质选择加热热源及确定加热温度；针对铺放过程将铺放区域划分为预加热区、空气冷却区Ⅰ、主加热区、空气冷却区Ⅱ和特殊冷却区，分别建立相应区域的传热方程并确定边界条件；运用结晶动力学理论推导冷却过程中结晶温度与相对结晶率之间的关系式；将预浸丝表面粗糙度评价指标Ra和RSm引入铺层紧密接触模型，得到铺放压力、施压时间、表面粗糙度与紧密接触度之间的关系。针对具体算例，给出各铺放参数的确定方法，并通过Matlab与Ansys软件对各铺放参数进行计算，分析得到各铺放参数的合理数值；最后，对铺放参数进行了实验验证。复合材料铺层相邻丝束之间的间隙或重叠不仅会影响复合材料构件的形状精度、增加铺放过程的剪切和重送操作，还对铺层整体力学特性产生较大的影响。因此，自动纤维丝铺放轨迹规划算法研究的主要目的就是设计合理的铺放路径，以消除或减少相邻丝束间的间隙或重叠现象。为避免除零件端面外的剪切和重送操作，提出了一种变角度轨迹规划算法。通过锥壳、非可展回转外壳和非可展变截面接头三种典型零件，对上述变角度轨迹规划算法进行了验证，并对上述零件变角度轨迹规划算法具体实现步骤及算法的可实现性进行了分析。自动纤维丝铺放设备后置处理技术是将轨迹规划算法得到的轨迹点坐标及方向数据转化成铺放设备各个运动轴可以识别的数据格式。自动纤维丝铺放设备由手臂部分和主轴部分组成，在对手臂部分后置处理算法进行研究时，将以往研究中压辊与铺放头固结的情况转变为压辊绕其中心转动的情况建立运动学模型，较之前的模型更符合实际铺放情况，更为精确。这种建模方式导致手臂部分冗余自由度的引入，在进行逆运动学求解时，以铺放头悬臂最短为优化目标，实现了冗余系统逆运动学的求解。对主轴部分后置处理算法进行了恒转角和变转角两种方法的研究，给出了这两种方法的实现方式及优缺点。此外，还对锥壳零件变角度轨迹规划算法及后置处理算法进行了实验验证。变角度铺放成型的复合材料铺层与传统定角度铺放成型的铺层相比，具有设计灵活和可充分发挥复合材料各向异性特性的优点。通过改变铺放路径上每一位置的铺放角，可以改变铺层内应力分布形式，同时还可以改变整体铺层的固有频率以避免系统发生共振。以锥壳零件变角度铺放算法成型的八组不同初始铺放角的铺层为研究对象，分别对各组铺层进行了静力学、模态和屈曲分析研究。研究内容包括复合材料变角度铺层有限元模型的建立方法、变角度铺层应力应变、模态、屈曲强度随初始铺放角的变化规律；研究基于各向异性材料理论、薄壳平衡方程、几何方程及物理方程、有限元模态分析理论和线性屈曲分析理论，并通过ABAQUS有限元软件对上述模型进行了计算分析。更多还原

【Abstract】 Automated fiber placement technology, as one of the extreme manufacturingtechnologies for large or extra large composite components with complex surfaceshapes, has been widely used in the field of aerospace vehicles. Automated fiberplacement technology uses thermoplastic towpreg as raw material and in-situconsolidation technology as curing method. Compared with the autoclave curingtechnology, it can get rid of the restriction of the autoclave on the demension of thecomposite components. It can also improve the production efficiency and reduce thecost effectively. Thus, the thermoplastic towpreg automated fiber placement hasbecome one of the key technologies for manufacturing the complex surface shapecomposite components and attracted more and more attention. To fabricate thequalified composite components using the automated fiber placement technique, notonly the thermoplastic towpreg and the fiber placement equipment are needed, butalso the thermoplastic towpreg placment process, the trajectory planning algorithm,the post processing algorithm of fiber placement device and the mechanicalproperties of the laminations need to be studied.The combination of thermoplastic towpreg and in-situ consolidation technologyin automated fiber placement process can achieve the preforming and the finalforming of the composite components simultaneously, but the parameters for theplacement process are quite critical. Therefore, the research on the automated fiberplacement process would be beneficial for choosing placement parameters, andensure the design specifications of the composite components. In this paper, theheating process, the cooling process and the degree of intimate contact in automatedfiber placement are studied including the selection of heat sources and proper heattemperature according to the physical properties of the thermoplastictowpreg(APC-2); the establishment of the heat transfer model and boundaryconditions of different placement areas which are divided on the basis ofmanufacturing process means preheating area, air cooling area Ⅰ, main heating area,air cooling area Ⅱ and special cooling area; based on crystallization kinetics theory,the relationship of crystallization temperature and relative crystallization rate isdeduced; the surface roughness evaluation parameters Ra and RSm of the towpregsare introduced to the model of the intimate contact and the relationship of theplacement pressure, pressure time, the surface roughness and the intimate contact isobtained. For the specific computing example, the methods of determining theplacement parameters are given, the placement parameters are calculated by Matlabor Ansys software, the reasonable placement parameters are obtained, and the placement parameters are validated by experiment.Overlap and gap of adjacent towpreg would, on one hand, affect the shapeaccuracy of composite components, and increase the operation of cut and re-send;on the other hand, have a great impact on the overall mechanical properties.Therefore, the main purpose of the trajectory planning algorithm for the automaticfiber placement is to design reasonable placement paths in order to reduce oreliminate the gap or overlap of adjacent towpregs. To avoid the cut and re-sendoperations except for the end faces, a variable angle trajectory planning algorithm isbrought out. The variable angle trajectory planning algorithm has been applied tothree typical components including the conical shell component, thenon-developable rotary shell component and the non-developable variablecross-section connection component. All the above mentioned examples verified thevariable angle trajectory planning algorithm, the detailed implementation steps andthe implementability analysis are also included.The post processing technology of automated fiber placement device is totransfer the coordinates and direction data of trace points obtained from thetrajectory planning algorithm into the data format which can be recognized by eachmotion axis of fiber placement device. Automated fiber placement device isconsisted of the arm part and the spindle part. A kinematic model was established inthe post processing research of the arm part which considered the rotation degree ofthe roller on the placement head. Compared with the model which simplified theroller as a fixed point on the placement head, this one better matches the acutal fiberplacement process and is more accurate. The model introduces a redundant degreeof freedom, thus the minimum length of the arm part can be considered as anobjective function to establish an optimization problem. Under this consideration,the inverse kinematic problem can be solved. The constant and variable anglepost-processing algorithms of spindle are studied, the applications, the advantagesand disadvantages of these two methods are given. The variable angle trajectoryplanning algorithm and the post processing algorithm are also verified via thefabrication of a cone shell.Compared with the traditional fixed-angle laminations, the variable anglecomposite laminations are featured with flexible designs and can fully take theadvantages of the anisotropic composite materials. By changing the fiber placingangle of each position in the placing path, the stress distribution of the laminationscan be changed. This would be helpful to avoid the system resonance by changingthe inherent frequency. Taking the conical shells with8different initial placementangles to study, the static analysis, the modal analysis and the buckling analysis areconducted. The research contents include the method for establishing the finiteelement model of composite variable angle laminations and the change rule of stress, strain, modal and buckling strength of laminations with initial placement angle. Thestudy bases on the finite element model of the laminations, derivation of anisotropicmaterial property theories, shell equilibrium equations, geometric equations andphysics equations, introduction of the finite element modal analysis theory and thelinear buckling analysis theory. Then the above-mentioned models are solved by useof ABAQUS, and the results are analyzed.更多还原