拓扑优化与增材制造结合:一种设计与制造一体化方法

被誉为"第三次工业革命"的增材制造技术通过材料层层累加的方式实现结构的制备,这种独特的制造方式实现了高度复杂结构的自由"生长"成形,极大地拓宽了设计"空间",为新型结构及材料的制备提供了强大的工具。制造工艺的飞速发展往往需要设计技术的快速跟进,拓扑优化方法因其不依赖初始构型及工程师经验,可获得完全意想不到的创新构型,已成为结构创新设计的重要工具。因此,将拓扑优化(先进设计技术)与增材制造(先进制造技术)融合,发展面向增材制造的创新设计技术具有广阔的前景。从面向增材制造的优质结构构型设计以及考虑增材制造工艺约束的拓扑优化设计方法两个方面,介绍了现阶段基于拓扑优化方法所建立的结构创新设计理论,并指出未来研究的趋势。     

航天高性能薄壁构件的材料-结构一体化设计综述

新一代航天器技术的快速发展对结构件超强承载、极端防热、超高精度和超轻量化提出了越来越苛刻的要求，如何设计并制造出高性能、轻量化、超精密的航天薄壁构件成为先进材料与结构设计制造领域普遍关注的难题。本文综述了近年来薄壁构件高性能设计与制造及其航天应用的主要成果，围绕材料-结构多尺度建模与性能表征、多材料多尺度结构设计与增材制造原理、增材制造材料性能与结构设计的交互作用机制等科学问题，就结构优化中的制造工艺约束建模，增材制造工艺参数对结构性能的影响，高性能构件材料-结构一体化设计方法及其在航天结构中的应用展开论述，并展望了未来典型航天薄壁构件材料-结构一体化设计和制造方法发展前景与应用，为未来相关研究工作和航空航天装备研发提供参考。     

面向增材制造的拓扑优化技术发展现状与未来

增材制造技术通过材料逐层打印制备结构,为复杂构件制造提供了新的成形方式。拓扑优化因不依赖于初始构型的选择,可设计出传统理念难以获得的创新构型,已成为航空航天和高端装备领域高性能、轻量化结构设计的重要手段。拓扑优化与增材制造有机融合,充分发挥各自优势和潜力,在现代制造业中展现出广阔应用前景。回顾了近年来关于增材制造与拓扑优化技术融合研究的主要内容和应用成果,包括以材料结构一体化为核心的多尺度/多层级结构优化设计、以设计制造一体化为核心的考虑增材制造工艺约束的优化方法等。同时,也分析了未来研究工作中存在的问题与挑战,如点阵结构性能表征及其尺度关联效应、增材制造材料成形各向异性、功能梯度材料与结构、增材制造材料与结构疲劳特性等对设计方法和成形工艺带来的挑战,为未来相关研究工作和航空航天应用提供参考。     

大型整体金属结构增材制造技术适航验证

针对民用飞机主承力结构金属增材制造技术适航验证方面存在的问题,开展金属结构增材制造技术适航验证研究。通过增材制造技术适用适航条款分析,给出了民用飞机金属结构增材制造技术适航验证思路,包括材料规范的建立、增材制造工艺的认证、材料强度性能的确定、结构特殊系数的选取和结构性能的验证,对每项验证方法给出了具体实施途径。以某型号前起落架支柱外筒增材制造A-100超高强度钢为例,给出了大型整体金属结构增材制造技术适航验证具体实施方案。     

增材制造600℃高温钛合金研究进展

先进航空发动机高压压气机550～600℃环境使用的关键/重要件对600℃高温钛合金提出迫切需求。但是,难成形的复杂构件以及梯度/复合结构与功能一体化构件等的制造,采用传统铸造、锻造等工艺技术难以满足需求和研发要求。增材制造是先进制造技术的典型代表,拥有材料设计-制造一体化、复杂设计-定制一体化等独特优势,为600℃高温钛合金新材料/新技术研发提供了新的途径。目前国内外已开始关注通过增材制造的方式制备600℃高温钛合金,重点研究材料-工艺-组织-性能的关系。本文首先简要回顾600℃高温钛合金研究,其次重点介绍不同增材制造工艺下600℃高温钛合金沉积态和后处理态的微观组织特点;在综合性能研究方面,列举并分析拉伸性能、蠕变性能、热疲劳性能和抗氧化性能等关键性能;在复杂设计/复合结构章节,论述以600℃高温钛合金为基体的复合材料和梯度结构增材制造的研究进展。最后,对增材制造600℃高温钛合金材料开发、复合工艺探索、缺陷控制和性能评价标准建立等研究方向进行展望。     

航空装备电子束增材制造技术发展及路线图

增材制造技术在航空装备领域具有广泛的发展前景。作为重要的金属增材制造工艺方法，电子束增材制造正处于快速发展阶段。电子束熔丝增材制造技术可满足航空大尺寸结构件的快速低成本制造，并可用于高价值零件的修复。电子束选区熔化增材制造技术在复杂结构以及难熔合金制件的制造方面具有显著优势。本文在对国内外电子束增材制造技术现状和发展趋势分析的基础上，从发展需求、目标、共性关键技术、应用、战略支撑与保障5个方面综合分析，绘制了面向2035年的航空装备电子束增材制造技术路线图，以期为航空装备电子束增材制造技术发展提供参考。     

增材制造技术在航空装备深化应用中的研究

增材制造技术对飞机结构研制起到了重要作用,但其应用潜力尚未完全发挥.通过梳理增材制造技术在航空装备中的应用现状与特点,分析了增材制造技术在航空领域的应用发展趋势,并从结构设计、专用材料、制造工艺、性能验证4个方面对制约增材制造技术全面深化应用的关键因素进行了分析探讨.     

增材制造损坏替换件拓扑优化设计方法

应急保障和战时抢修是增材制造技术发展的重要方向之一,也给面向增材制造的结构优化设计提出了新的挑战。为了实现异种材料原位替换件的构型设计,提出增材制造损坏替换件拓扑优化设计方法,并以机用散热风扇为例开展应用研究。通过分析散热风扇服役环境和战时抢修需求,在变密度方法框架下建立结构总重量和转动惯量控制在原件数据附近小范围以内、以结构整体柔顺度最小化为目标的拓扑优化问题列式,并完成灵敏度分析公式推导。从拓扑优化结果及其重构模型的仿真数据可知：散热风扇替换件拓扑优化结果收敛性好、满足所有设计要求,重构方案满足增材制造工艺性要求,验证了本文设计方法的有效性。     

激光增材制造过程数值仿真技术综述

数值仿真是研究激光增材制造过程中各类物理现象、揭示零件缺陷形成机理、优化增材制造工艺参数的重要手段,该领域学者针对增材制造过程中的热分析、金属粉末颗粒性质分析、微观结构分析、质量缺陷成因分析等方面,开展了大量研究,提出了相应的数学模型和方法。激光增材制造过程的数值仿真是一个在空间和时间上均跨越多个尺度的复杂问题,微观、介观、宏观尺度下数值仿真所关注的对象和所使用的方法各不相同;多数研究聚焦于某一尺度下的过程仿真,另一部分研究则基于不同模型的数据关系建立模型间的耦合关系,实现热-相、热-力的综合分析。对现阶段激光增材制造数值仿真领域的主要技术进行了综述,在梳理数值仿真基本流程的基础上,对其中涉及的热源模型,粉末模型,力学模型以及微观结构模型进行了介绍,讨论了其特点和适用性;结合相关技术领域的发展,探讨了激光增材制造数值仿真技术的发展方向,旨在为本领域的技术研究与发展提供参考。     

铝合金增材制造的发展现状与展望北大核心CSCD

铝合金增材制造凭借着材料自身的轻量化优势以及增材制造工艺在材料利用率和复杂结构制造方面的特点,在航天领域结构件的制造方面受到了广泛关注。本文针对铝合金增材制造在航天领域的应用,通过电弧熔丝、激光选区熔化以及激光送粉三个代表性工艺分析铝合金增材制造技术的研究现状及现存问题,并简要阐述了目前铝合金增材制造技术在航天领域的应用现状和未来的发展方向。     

A review of topology optimization for additive manufacturing: Status and challenges

Topology optimization was developed as an advanced structural design methodology to generate innovative lightweight and high-performance configurations that are difficult to obtain with conventional ideas. Additive manufacturing is an advanced manufacturing technique building as-designed structures via layer-by-layer joining material, providing an alternative pattern for complex components. The integration of topology optimization and additive manufacturing can make the most of their advantages and potentials, and has wide application prospects in modern manufacturing. This article reviews the main content and applications of the research on the integration of topology optimization and additive manufacturing in recent years, including multi-scale or hierarchical structural optimization design and topology optimization considering additive manufacturing constraints. Meanwhile, some challenges of structural design approaches for additive manufacturing are discussed, such as the performance characterization and scale effects of additively manufactured lattice structures, the anisotropy and fatigue performance of additively manufactured material, and additively manufactured functionally graded material issues, etc. It is shown that in the research of topology optimization for additive manufacturing, the integration of material, structure, process and performance is important to pursue high-performance, multi-functional and lightweight production. This article provides a reference for further related research and aerospace applications.     

An aerospace bracket designed by thermo-elastic topology optimization and manufactured by additive manufacturing

Combination of topology optimization and additive manufacturing technologies provides an effective approach for the development of light-weight and high-performance structures. A heavy-loaded aerospace bracket is designed by topology optimization and manufactured by additive manufacturing technology in this work. Considering both mechanical forces and temperature loads, a formulation of thermo-elastic topology optimization is firstly proposed and the sensitivity analysis is derived in detail. Then the procedure of numerical optimization design is presented and the final design is additively manufactured using Selective Laser Melting (SLM). The mass of the aerospace bracket is reduced by over 18%, benefiting from topology and size optimization, and the three constraints are satisfied as well in the final design. This work indicates that the integration of thermo-elastic topology optimization and additive manufacturing technologies can be a rather powerful tool kit for the design of structures under thermal-mechanical loading.     

增材制造阵风锁支座的装机应用研究

根据3D 打印技术的装机推进要求，在完成材料及工艺的验证后，即开始进行试片级增材制造材料许用值试验以及增材制造零件级试验。增材制造的零件由于其工艺特点，通常X-Y 方向与Z 方向力学性能有差异，与传统金属零件设计时各向同性的特点有差异，因此有必要在接近真实飞行状态下测试其力学性能。以增材制造阵风锁支座为例，计算飞机运营过程中最大载荷状态，选取最典型的载荷方向进行工装试验方案设计；在试验开始前，进行工程计算和软件仿真，预测失效模式和失效载荷。结果表明：软件仿真和工程计算的结果准确有效，增材制造钛合金阵风锁支座的力学性能稳定，能够承受极端工况的考验，满足装机要求。     

Layout design of thin-walled structures with lattices and stiffeners using multi-material topology optimization

In this paper, the thin-walled structures with lattices and stiffeners manufactured by additive manufacturing are investigated. A design method based on the multi-material topology optimization is proposed for the simultaneous layout optimization of the lattices and stiffeners in thin-walled structures. First, the representative lattice units of the selected lattices are equivalent to the virtual homogeneous materials whose effective elastic matrixes are achieved by the energy-based homogenization method. Meanwhile, the stiffeners are modelled using the solid material. Subsequently, the multi-material topology optimization formulation is established for both the virtual homogeneous materials and solid material to minimize the structural compliance under mass constraint. Thus, the optimal layout of both the lattices and stiffeners could be simultaneously attained by the optimization procedure. Two applications, the aircraft panel structure and the equipment mounting plate, are dealt with to demonstrate the detailed design procedure and reveal the effect of the proposed method. According to numerical comparisons and experimental results, the thin-walled structures with lattices and stiffeners have significant advantages over the traditional stiffened thin-walled structures and lattice sandwich structures in terms of static, dynamic and anti-instability performance.     

金属增材制造数据处理与工艺规划研究综述

金属增材制造数据处理与工艺规划是金属增材制造软件系统的核心,涵盖了金属支撑结构设计、模型切片以及路径规划等内容,决定着最终金属零部件的产品性能。从金属增材制造模型前处理出发,较为全面地概述了与之相关的多类型支撑设计和新型支撑优化等数据处理内容,针对金属增材制造数据处理中模型切片这一关键环节,分别从平面切片、自适应切片和曲面切片等方面进行了研究进展综述,同时对金属增材制造工艺中的路径规划研究进展进行了概述,最后对其发展趋势做了初步展望。     

微小型航空燃气轮机离心叶轮拓扑优化设计

离心叶轮是微小型航空燃气轮机中的关键部件,要求其在满足气动性能的前提下,尽量减轻结构重量,传统设计制造技术已基本发挥到极致,但增材制造技术及拓扑优化设计方法的发展为其进一步优化设计拓展了新的空间。针对某型航空微型燃气轮机离心叶轮减重设计问题,依托增材制造和拓扑优化设计技术,在现有设计的基础上,首先对离心叶轮进行静强度分...     

激光增材制造高强高韧TC11钛合金力学性能及航空主承力结构应用分析

随着损伤容限设计理念发展和轻量化要求提高,高强高韧钛合金逐渐成为航空装备关键主承力构件主要结构材料。激光增材制造制备钛合金大型主承力构件具有数字化、短周期、低成本等技术优势,特别是激光增材制造过程超常固态相变动力学条件为制备高强高韧钛合金提供了新的机会。本文根据航空主承力结构选材性能要求,对激光增材制造TC11钛合金静强度、疲劳和损伤容限特性进行测试与分析,在此基础上对其在航空主承力结构的应用前景进行分析。结果表明,激光增材制造TC11钛合金力学性能具有显著的高强高韧和低屈强比特征,其疲劳缺口敏感性和裂纹扩展速率低,性能分散性小,综合性能满足航空主承力结构选材要求。与目前航空主承力结构广泛应用的TC4-DT损伤容限型钛合金相比,激光增材制造TC11高强高韧钛合金损伤容限特性相当、疲劳性能有所改善、许用应力提高23%,结构具有进一步减重优势。激光增材制造TC11钛合金优异的强韧性匹配在提高结构许用应力的同时可避免大厚度结构发生脆性断裂,其低疲劳缺口敏感性和优异的疲劳裂纹扩展特性对于结构服役安全具有重要意义。     

Collaborative optimization design of process parameter and structural topology for laser additive manufacturing

High-resolution laser additive manufacturing (LAM) significantly releases design freedom, promoting the development of topology optimization (TO) and advancing structural design methods. In order to fully take advantage of voxelated forming methods and establish the quantitative relationship between the mechanical properties of printing components and multiple process factors (laser- and process- parameters), the concurrent optimization design method based on LAM should cover the process-performance relationship. This study proposes a novel artificial intelligence-facilitated TO method for LAM to concurrently design microscale material property and macroscale structural topology of 3D components by adopting heuristic and gradient-based algorithms. The process–structure–property relationship of selective laser sintering is established by the back propagation neural network, and it is integrated into the TO algorithm for providing a systematic design scheme of structural topology and process parameter. Compared with the classical optimization method, numerical examples show that this method is able to improve the mechanical performance of the macrostructure significantly. In addition, the collaborative design method is able to be widely applied for complex functional part design and optimization, as well as case studies on artificial intelligence-facilitated product evaluation.     

A fully automated framework for helicopter rotor blades design and analysis including aerodynamics,structure, and manufacturing

This study describes an integrated framework in which basic aerospace engineering aspects (performance, aerodynamics, and structure) and practical aspects (configuration visualiza-tion and manufacturing) are coupled and considered in one fully automated design optimization of rotor blades. A number of codes are developed to robustly perform estimation of helicopter config-uration from sizing, performance analysis, trim analysis, to rotor blades configuration representa-tion. These codes are then integrated with a two-dimensional airfoil analysis tool to fully design rotor blades configuration including rotor planform and airfoil shape for optimal aerodynamics in both hover and forward flights. A modular structure design methodology is developed for real-istic composite rotor blades with a sophisticated cross-sectional geometry. A D-spar cross-sectional structure is chosen as a baseline. The framework is able to analyze all realistic inner configurations including thicknesses of D-spar, skin, web, number and ply angles of layers of each composite part, and materials. A number of codes and commercial software (ANSYS, Gridgen, VABS, PreVABS, etc.) are implemented to automate the structural analysis from aerodynamic data processing to sec-tional properties and stress analysis. An integrated model for manufacturing cost estimation of composite rotor blades developed at the Aerodynamic Analysis and Design Laboratory (AADL), Aerospace Information Engineering Department, Konkuk University is integrated into the framework to provide a rapid and dynamic feedback to configuration design. The integration of three modules has constructed a framework where the size of a helicopter, aerodynamic performance analysis, structure analysis, and manufacturing cost estimation could be quickly investigated. All aspects of a rotor blade including planform, airfoil shape, and inner structure are considered in a multidisciplinary design optimization without an exception of critical configuration.