Advanced Multifunctional and Multiphysics Metamaterials for Mechanical Element Design

经过世纪的汽车工业的进步，大约85%的燃料能源仍然浪费在汽车和空气中。类似的情况也发生在农业机械、火车和飞机上。能源浪费不仅影响经济，而且影响环境。智能材料是减少能源消耗和从这些浪费的能源中收集能量的有前途的替代方案之一。正在开发具有多功能和能量收集能力以及低能耗水平的智能多物理场材料，以提供智能自供电传感器和执行器。轻质蜂窝材料是减少能源消耗的另一种选择。多孔固体为需要轻质和刚性部件的应用提供了一种坚固的低质量替代品。由重复单位单元形成的细胞基超材料也使工程师能够实现超越自然界的物理特性。受生物系统的启发，其中集成了结构特性，传感，致动和自我修复，智能多功能超材料可以作为一种强大的，具有成本效益的替代方案来集成智能材料和超材料的多种功能。多功能材料不仅可以作为能量收集器，还可以作为结构元件、自供电电气设备、自集成热交换器以及通过嵌入式燃料电池或光电转换器的电源。增材制造的进展表明，制造多功能超材料是可行的。

After more than a century of advances in the automotive industry, about 85 percent of fuel energy is still wasted in cars and is lost in the air. Similar scenarios occur with agricultural machines, trains, and airplanes. The energy waste does not only affect the economy, but also the environment. Smart materials are one of the promising alternatives for the reduction of energy consumption and for harvesting energy from these wasted energy resources. Smart multiphysics materials with multifunctional and energy harvesting abilities and a low level of energy consumption are being developed to provide intelligent self-powered sensors and actuators. Lightweight cellular materials are another alternative to reduce energy consumption. Cellular solids offer a robust low-mass alternative for applications requiring lightweight and stiff components. Cellular-based metamaterials fashioned by repeating unit cells have also enabled engineers to achieve physical properties beyond those found in nature. Inspired by biological systems, in which structural properties, sensing, actuating, and self-healing are integrated, smart multifunctional metamaterials can be introduced as a robust, cost-effective alternative to integrate multiple functionalities of smart materials and metamaterials. Multifunctional materials can not only serve as energy harvesters, but also as structural elements, self-powered electric devices, self-integrated heat exchangers, and power sources via embedded fuel-cells or photovoltaics. Advances in additive manufacturing have shown that fabricating multifunctional metamaterials is feasible.