Design of novel, additively manufactured cellular lattice supported composite structures using topology optimisation

由于三个重要因素，提高风能产能的生产在国内和全球都非常重要。首先，燃烧化石燃料产生的温室气体和其他排放物造成的污染加剧了全球变暖。这些影响增加了气候的不稳定性，导致更多的自然灾害和生态系统崩溃。其次，过度依赖化石燃料的能源导致国家之间和国家内部的不安全和紧张局势。第三，增加风能装机容量是一种经济效益。风能在生产能源方面具有很高的成本效益，风能产业的投资可以在制造业、建筑业、运营和维护方面创造就业机会，从而推动经济增长。新技术和能源储存网络的发展也有助于降低风能和其他形式的可再生能源的成本。加快风能产能生产的最大障碍之一是制造风力涡轮机转子叶片的成本和交货时间。风力叶片的规模越来越大，这意味着与材料、劳动力和工具相关的主要制造成本是一个限制因素。建议制造一个作为叶片内部结构的模具，通过实现自动化和减少材料使用，消除昂贵的钢背复合模具的需要，从而针对这些成本来源中的每一个。增材制造（AM）是一种使能技术，对未来生产大规模结构至关重要。它对叶片生产的主要作用是更有效地利用材料和分工。增材制造可以使用拓扑优化（TO）来设计大型结构。TO提供了一种针对特定性能需求设计结构的方法。增材制造允许创建这些定制的结构，使这两种技术成为生产满足特定需求的结构的理想匹配。TO和AM的结合导致了高效结构的创建，浪费最少，生产速度最快。在风力叶片设计中使用拓扑优化存在两个主要挑战。首先，叶片的气动弹性响应是结构设计中的一个重要因素，因为它可以通过优化刚度和调整固有频率来提高叶片从风中捕获能量和减轻载荷的能力。拓扑优化并不容易与气动弹性求解器兼容，因此将气动弹性设计与拓扑优化相结合的研究有限。其次，由于弯矩臂的尺寸，复合层压板是大型风力涡轮机叶片的关键部件。考虑到计算密集型的过程，正交异性层压板和多种材料的拓扑优化在其设计大规模可制造结构的能力方面受到限制。提出了一种设计方法，该方法利用拓扑优化和增材制造的优势来实现优化的复合材料层压板配置以及风力涡轮机叶片的重复单元格梯度晶格结构。该方法涉及一个多阶段拓扑优化过程；在第一阶段，基于理想拓扑优化方案设计复合材料层压结构；在第二阶段，第一阶段的结果被冻结并用于设计3D打印的重复单元格结构，该结构支持复合层压板，并允许提高可制造性。该工艺的目标是将传统的结构要求知识结合起来，以有效地使用复合材料层压板配置，同时也使增材制造能够支持和提高性能、重量和制造成本。

Upscaling the production of wind energy capacity is of great importance domestically and globally due to three significant factors. Firstly, pollution from greenhouse gases and other emissions as a result of burning fossil fuels for energy contributes to global warming. These effects cause increased instability of the climate, resulting in more natural disasters as well as ecosystem collapse. Secondly, over-dependence on fossil fuel for energy causes insecurity and tensions between and within nations. Thirdly, increasing the installed capacity of wind energy is an economic benefit. Wind energy is highly cost efficient for producing energy and the investment in the wind industry drives economic growth due to job creation in manufacturing, construction, and operation and maintenance. The development of new technology and energy storage networks also helps to lower costs of wind and other forms of renewable energy. One of the largest barriers to faster production of wind energy capacity is the cost and lead time of manufacturing wind turbine rotor blades. The growing scale of wind blades means that the main costs of manufacturing which are associated with materials, labour, and tooling, are a limiting factor. It is proposed that manufacturing a mould which acts as the internal structure of the blade would target each of these sources of cost through enabling automation and reduced material use by removing the need for expensive steel-backed composite moulds.Additive manufacturing (AM) is an enabling technology which is crucial for producing large scale structures in future. It's main function for wind blade production is more efficient use of material and division of labour. AM enables the use of topology optimisation (TO) for the design of large structures. TO provides a means to design structures for specific performance needs. AM allows for the creation of these structures that have been customized, making the two technologies an ideal match for producing structures that are designed to meet specific needs. The combination of TO and AM leads to the creation of structures that are highly efficient with minimal waste and maximum speed in production.There are two main challenges associated with using topology optimisation in wind blade design. Firstly, the aeroelastic response of the blade is an important factor in the structural design, as it can improve the blade's ability to capture energy from the wind and alleviate loads by optimising the stiffness and tuning the natural frequencies. Topology optimisation is not readily compatible with aeroelastic solvers and there is limited research combining aeroelastic design with topology optimisation due to this difficulty. Secondly, composite laminates are critical component of large wind turbine blades, due to the size of the bending moment arms. Topology optimisation of orthotropic laminates and multiple materials is limited in its ability to design large scale, manufacturable structures, given the computationally intensive process.A design methodology is proposed, which leverages the strengths of topology optimisation and additive manufacturing to achieve optimised composite laminate configurations as well as repeated unit cell graded lattice architectures for wind turbine blades. The method involves a multi-stage topology optimisation process; In the first stage, a composite laminate structure is designed based on an idealised topology optimisation solution; In the second stage, the results from the first stage are frozen and utilised to design a 3D printed repeated unit cell architecture which supports the composite laminates and allows for improved manufacturability. The goal of this process is to combine conventional knowledge of structural requirements for efficient use of composite laminate configurations, while also enabling the inclusion of additive manufacturing to support and improve performance, weight and manufacturing cost.