点击上方蓝字，关注我们！受植物种皮微观结构的启发，中国研究人员开发了一种可弯曲、可恢复并承载负荷的金属材料，为实用变形机翼开辟了新途径。当工程师们谈及能在飞行中改变形状的飞机时，话题几乎总会转向鸟类。数十年来，自然界中的飞行者一直是变形飞机研究的蓝图。然而，来自中国的一项新研究却另辟蹊径。研究人员没有仰望天空，而是俯视大地，从植物种子的微观结构中获得了灵感。南京航空航天大学（NUAA）的一个团队开发出一种能够弯曲、恢复形状并承载空气动力学载荷的金属材料，这一组合长期以来一直困扰着航空航天工程师。这项发表在《 International Journal of Extreme Manufacturing》上的工作表明，未来的飞机机翼可能更多地借鉴植物而非鸟类。变形飞机机翼的想法并不新鲜。设计师长期以来一直主张，能够变形的机翼可以通过持续适应不同飞行阶段，提升燃油效率、延长航程并增强控能力。然而，实际上这些材料始终未能达到预期。目前大多数设计都依赖于被动结构，这类结构能够轻微弯曲但无法主动改变形状。还有一些则使用基于聚合物的材料，这些材料会对热或电输入做出反应，但它们往往缺乏用于航空航天领域的所需强度。为弥补这一问题，工程师们增加了电机、铰链和执行器，这些解决方案有效，但代价是重量、复杂性和可靠性。结果形成了一种悖论：机翼越灵活，往往越重、效率越低。NUAA团队从一个意想不到的角度切入了这个问题。他们没有试图复制鸟类飞行，而是研究某些植物如何在显微镜层面管理压力和运动。它们的灵感来自常见多肉植物马齿苋的种皮。在显微镜下观察该种子的外层，可以看到由波浪形界面和嵌入的特征组成的网络结构，这种结构在种子膨胀或变形时能够均匀分散应力。与依赖骨骼、肌肉和羽毛的鸟类翅膀不同，种皮仅通过结构就实现了灵活性和韧性。这一理念，即几何形状而非机械装置，成为了研究人员设计的基础。为了将这一自然概念转化为工程现实，研究人员转向了一种镍钛形状记忆合金，这种金属以其在加热时能够“记住”并恢复到预设形状的能力而闻名。团队利用激光粉末床熔化技术，即一种高精度金属 3D 打印技术，制造出了一系列的微型蜂窝结构，其胞壁厚度仅为 0.3 毫米。这些波浪状、相互连接的图案与植物种皮中所呈现的应力扩散几何结构十分相似。 与传统的金属晶格不同，该结构并非被动结构。形状记忆合金能自我驱动。受热时材料弯曲；冷却时变硬，无需外部电机或机械连接装置。通过调整蜂窝结构中每个交汇处的壁面数量，研究人员能够调节材料的泊松比，泊松比值是一种衡量材料在拉伸时膨胀或收缩的度量。有些结构在受到拉力时会向两侧扩张，而有些则会收缩，这为设计师提供了丰富的机械“素材库”以供使用。在所测试的设计方案中，六边形蜂窝结构尤为突出。其在断裂前的伸展幅度可达 38%，而在受热后又能恢复超过 96%的原始形状，这些数据在能够承载重物的金属材料中是极为罕见同时出现的。为了体现其在实际应用中的可行性，该团队并未止步于材料样本阶段。他们使用新型材料建造了原型机翼部分，并测试了其变形的流畅性。这些机翼部分能够在角度范围从 -25 度到 +25 度之间改变形状，即便是在与飞行过程中所遇到的温度相当的条件下也是如此。关键在于，这种运动是连续平滑的，而不是断续或突兀的，并且不需要笨重的执行器。实际上，机翼蒙皮本身既成为结构，也成为机构。这项工作的意义不在于单一翼原型，而在于它所体现的更广泛的设计理念。通过将受自然启发的结构与活性金属合金结合，NUAA团队为开发比以往尝试更轻、更简单、更坚固的变形飞机表面铺平了道路。 因为驱动来自材料本身，该设计避免了与电机、铰链和执行器相关的许多故障点。这对飞机效率、可靠性和维护都具有重要意义。研究人员强调，目前研究仍处于早期阶段。下一步包括集成传感器和电子系统，使未来版本的材料能够自行监测形状并自动响应变化的条件。长远愿景是飞机表面能够感知气流、温度或负载，并实时进行自我调整，这并非仅通过软件指令实现，而是依靠嵌入结构层面的材料智能来达成。如果这一愿景得以实现，变形飞机的未来或许将不再依赖于借鉴鸟类翅膀，而更多地归功于植物种子那默默无闻的非凡创造力。Forget birds: A plant seed has inspired a breakthrough in morphing aircraft wingsInspired by the microscopic structure of a plant seedcoat, researchers in China have developed a metal material that bends, recovers and carries load, offering a new path toward practical shape-shifting aircraft wings.When engineers talk about aircraft that can change shape in flight, the conversation almost always turns to birds.Nature’s flyers have been the blueprint for decades of research into morphing aircraft.Yet a new study fromChina takes a very different route. Instead of looking to the sky, the researchers looked to the ground and found their inspiration in the microscopic structure of a plant seed.A team at Nanjing University of Aeronautics and Astronautics (NUAA) has developed a metal material that can bend, recover its shape, and carry aerodynamic loads, a combination that has long challenged aerospace engineers.The work, published in theInternational Journal of Extreme Manufacturing, suggests that future aircraft wings may owe more to botany than to birds.Why morphing wings remain one of aviation’s hardest problemsThe idea of morphing aircraft wings is not new. Designers have long argued that wings capable of changing shape could improve fuel efficiency, extend range, and enhance control by adapting continuously to different phases of flight.In practice, however, the materials have always fallen short.Most existing designs rely on passive structures that can flex slightly but cannot actively change shape. Others use polymer-based materials that respond to heat or electrical input, but these tend to lack the strength required for aerospace use.To compensate, engineers add motors, hinges, and actuators, solutions that work, but at the cost of weight, complexity, and reliability.The result is a paradox: the more adaptable the wing becomes, the heavier and less efficient it often is.How plants, not birds, inspired morphing aircraft wings The NUAA team approached the problem from an unexpected angle. Rather than trying to replicate bird flight, they studied how certain plants manage stress and movement at a microscopic level.Their inspiration came from the seedcoat of Portulaca oleracea, a common succulent. Under a microscope, the seed’s outer layer reveals a network of wavy interfaces and embedded features that distribute stress evenly as the seed swells or deforms.Building an active metal structure for morphing aircraft wingsTo translate this natural concept into engineering reality, the researchers turned to a nickel-titanium shape-memory alloy, a metal known for its ability to “remember” and return to a programmed shape when heated.What makes the study stand out is how the material was formed.Using laser powder bed fusion, a high-precision metal 3D-printing technique, the team created a family of tiny honeycomb structures with cell walls as thin as 0.3 millimetres. These wavy, interconnected patterns mirror the stress-spreading geometry seen in the plant seedcoat.Unlike traditional metal lattices, the structure is not passive. The shape-memory alloy provides its own actuation. When heated, the material bends; when cooled, it stiffens, without the need for external motors or mechanical linkages.Why Poisson’s ratio matters in morphing aircraft wing designOne of the key breakthroughs lies in how the structure handles deformation.By adjusting how many walls meet at each junction in the honeycomb, the researchers were able to tune the material’s Poisson’s ratio, a measure of how a material expands or contracts when stretched.Some configurations expanded laterally when pulled, while others contracted, giving designers a wide mechanical “palette” to work with. Among the tested designs, the hexagonal honeycomb stood out.It could stretch by up to 38 per cent before fracturing and recover more than 96 per cent of its original shape after heating, figures that are rarely seen together in metal metamaterials capable of carrying load.From laboratory samples to working wing sectionsTo demonstrate real-world relevance, the team did not stop at material samples. They built prototype wing sections using the new metamaterial and tested their ability to morph smoothly.The wing sections were able to change shape across an angle range from –25 degrees to +25 degrees, even at temperatures comparable to those encountered during flight.Crucially, the movement was continuous and smooth rather than stepped or jerky, and required no bulky actuators. In effect, the wing skin itself became both structure and mechanism.Why this approach matters for future aircraftThe significance of the work lies not in a single wing prototype, but in the broader design philosophy it represents.By combining a nature-inspired structure with an active metal alloy, the NUAA team has outlined a path toward morphing aircraft surfaces that are lighter, simpler, and more robust than previous attempts.Because actuation comes from the material itself, the design avoids many of the failure points associated with motors, hinges, and control rods. That has clear implications not only for aircraft efficiency, but also for reliability and maintenance.What comes next for shape-shifting metal wingsThe researchers emphasise that this is still early-stage work. Next steps include integrating sensors and electronic systems so future versions of the material can monitor their own shape and respond automatically to changing conditions.The long-term vision is an aircraft surface that senses airflow, temperature, or load and adjusts itself in real time, not through software commands alone, but through material intelligence embedded at the structural level.If that vision is realised, the future of morphing aircraft may owe less to feathers and flight muscles and more to the quiet ingenuity of a plant seed.Journal Reference：Chen, Wenxin,Gu, Dongdong,Liu, Xin,Sun, Yu,Sun, Jianfeng,Su, Fangyan,Zou, Jinwen,Chen, Yusheng.Laser printed bio-inspired active flexible metallic metamaterials with reconfigurable deformation capability[J].International Journal of Extreme Manufacturing,2026,8(2025122400):025005-025005.DOI：10.1088/2631-7990/ae2073.点击文首"新材料国际情报中心"或下方名片关注本公众号, 浏览更多内容。
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