Santee William R, Potter Adam W, Friedl Karl E
Biophysics and Biomedical Modeling Division, U.S. Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Building 42, Natick, MA 01760-5007.
Mil Med. 2017 Jul;182(7):e1702-e1705. doi: 10.7205/MILMED-D-16-00156.
Many people are unaware of the science underlying the biophysical properties of Soldier clothing and personal protective equipment, yet there is a well-refined biomedical methodology initiated by Army physiologists in World War II. This involves a methodical progression of systematic material testing technologies, computer modeling, and human testing that enables more efficient development and rapid evaluation of new concepts for Soldier health and performance. Sophisticated manikins that sweat and move are a central part of this testing continuum. This report briefly summarizes the evolution and use of one specialized form of the manikin technologies, the thermal hand model, and its use in research on Soldier hand-wear items that sustain dexterity and protect the hand in extreme environments.
Thermal manikin testing methodologies were developed to provide an efficient and consistent analytical tool for the rapid evaluation of new clothing concepts. These methods have been upgraded since the original World War II and Korean War eras to include articulation and sweating capabilities, as characterized and illustrated in this article. The earlier "retired" versions of thermal hand models have now been transferred to the National Museum of Health and Science.
The biophysical values from manikin testing are critical inputs to the U.S. Army Research Institute of Environmental Medicine mathematical models that provide predictions of soldier comfort, duration of exposure before loss of manual dexterity, and time to significant risk of freezing (skin temperature <-1°C) and nonfreezing cold injuries (skin temperature <5°C). The greater thickness of better insulated handwear reduces dexterity and also increases surface area which makes added insulation increasingly less effective in retaining heat. Measurements of both thermal resistance (insulation) and evaporative resistance (permeability) collectively characterize the biophysical properties and enable mathematical modeling of the human thermophysiological responses. This information can help guide the hand-wear development and selection process which often requires trade-offs between factors such as material, cost, and sizing.
Soldier hands provide fine motor dexterity in tactical functions, ranging from pulling a trigger to pulling a parachute ripcord; thus, protecting hand function is critical to soldier readiness. Also, the importance of protection against nonbattle cold injuries was highlighted during World War II in northern Europe, in the Aleutian Islands, and later in Korea. The U.S. Army has been on the forefront of the biophysical analysis of clothing including gloves since environmental research was established at the Armored Medical Research Laboratory and Climatic Research Laboratory during World War II. U.S. Army Research Institute of Environmental Medicine does not make the equipment but works with their Natick Soldier Research, Development, and Engineering Center partners to make the equipment better.
许多人并不了解士兵服装和个人防护装备生物物理特性背后的科学原理，然而，美国陆军生理学家在第二次世界大战期间开创了一套完善的生物医学方法。这涉及系统材料测试技术、计算机建模和人体测试的有序推进，从而能够更高效地开发并快速评估有关士兵健康和性能的新概念。能够出汗和移动的精密人体模型是这一测试连续过程的核心部分。本报告简要总结了人体模型技术的一种特殊形式——热手模型的演变和应用，以及它在研究能在极端环境中保持灵活性并保护手部的士兵手部穿戴物品方面的应用。
热人体模型测试方法的开发是为了提供一种高效且一致的分析工具，用于快速评估新的服装概念。自第二次世界大战和朝鲜战争初期以来，这些方法不断升级，已具备本文所描述和阐释的关节活动和出汗能力。早期的“退役”热手模型现已被移交至国立卫生科学博物馆。
人体模型测试得出的生物物理值是美国陆军环境医学研究所数学模型的关键输入数据，这些模型可预测士兵的舒适度、失去手部灵活性之前的暴露持续时间，以及出现严重冻伤风险（皮肤温度<-1°C）和非冻伤性冷损伤（皮肤温度<5°C）的时间。绝缘性能更好的手部穿戴物品厚度更大，这会降低灵活性，还会增加表面积，使得额外的绝缘在保暖方面的效果越来越差。热阻（绝缘）和蒸发阻力（透气性）的测量共同表征了生物物理特性，并能够对人体热生理反应进行数学建模。这些信息有助于指导手部穿戴物品的开发和选择过程，该过程通常需要在材料、成本和尺寸等因素之间进行权衡。
士兵的手在各种战术功能中提供精细运动灵活性，从扣动扳机到拉开降落伞开伞索；因此，保护手部功能对于士兵的战备状态至关重要。此外，在第二次世界大战期间的北欧、阿留申群岛以及后来的朝鲜，预防非战斗性冷损伤的重要性得到了凸显。自第二次世界大战期间在装甲医学研究实验室和气候研究实验室开展环境研究以来，美国陆军一直在服装包括手套的生物物理分析方面处于前沿位置。美国陆军环境医学研究所并不制造设备，而是与纳蒂克士兵研究、开发与工程中心的合作伙伴共同努力，以使设备更加完善。
