Aerodynamics, Wing Biomechanics, and the Evolutionary Diversification of the Chiroptera

进化新颖性的起源和阐述构成了进化研究中最基本的领域之一。有鉴于此，多年来，脊椎动物翅膀的结构、来源及其在飞行中的作用一直是生物学家和工程技术人员关注的问题。然而，对机翼结构部件内部力量的准确估计，以及对机翼形式和机翼运动模式的机械、空气动力学和能量意义的充分理解一直被忽视。因此，对飞行装置的进化起源和多样化历史的了解仍然很原始。在这项研究中，我们将模拟一只大型蝙蝠的飞行来分析空气动力学、力学和能量学。之所以选择蝙蝠作为我们的研究对象，是因为蝙蝠的解剖结构（由弹性翼膜连接的坚硬骨骼）相对容易以生物学现实的方式建模。PI将使用我们的计算机模拟来问：1)在飞行过程中，机翼上的联合力和力矩的大小是多少？翅膀内部的皮肤和骨骼应力有多大？2)机翼形态和运动学的小范围变化如何影响关节力和力矩以及机翼内部形成的皮肤和骨骼应力？3)机翼的哪些形态和运动学特征会影响机翼的机动性、结构稳定性和气动性能，以及飞行的机械动力？这些问题将通过完成一系列相互关联的目标来回答。将以灰头飞狐Pteropus poliocephalus为基础，开发一个机械上和生物学上逼真的飞行蝙蝠计算机模型，该物种已经获得了大量的功能和解剖信息。模型的输入将包括解剖信息，有关机翼组织力学特性的数据，以及机翼运动模式的三维描述。将建立一个详细的计算机模型，然后用于生成有关机翼关节处受力、翼骨和翼皮应力、飞行机械功率、翼骨抗屈曲能力以及机翼稳定性和可操作性的信息。将进行敏感性分析，以确定体型、翅膀形状、飞行速度和生物力学特性对模型输出的相对影响。本研究结果将为进一步研究蝙蝠飞行的起源、多样性和适应性奠定基础。

Swartz 9723736 The origin and elaboration of evolutionary novelty comprise one of the most fundamental areas of evolutionary inquiry. In this light, the structure of vertebrate wings, their derivation, and their function during flight have attracted the attention of biologists and engineers for many years. However, the accurate estimation of the forces developed within the structural components of the wing, and the full understanding of the mechanical, aerodynamic, and energetic significance of the wing form and wing movement patterns have been neglected. As a consequence, knowledge of the evolutionary origins and history of diversification of flight apparatus remains primitive In this study, we will model the flight of a large bat to analyze aerodynamics, mechanics, and energetics. A bat has been selected as our study organism because bats are characterized by an anatomical organization (rigid bony elements interconnected by an elastic wing membrane) that is relatively simple to model in a biologically realistic fashion. The PI will the use our computer simulation to ask: 1) what are the magnitudes of the joint forces and moments in the wing during flight? how large are the skin and bone stresses developed within the wing?; 2) how do small-scale variations in wing morphology and kinematics affect the joint forces and moments and the skin and bone stresses developed within the wing? 3) what features of wing morphology and kinematics affect the maneuverability, structural stability and aerodynamic performance of the wing, and the mechanical power of flight? These questions will be answered by accomplishing a series of interrelated objectives. A mechanically and biologically realistic computer model of a flying bat will be developed, based on Pteropus poliocephalus, the gray-headed flying fox, a species from which a great deal of functional and anatomical information has already been obtained. Inputs into the model will include anatomical information, dat a concerning the mechanical properties of wing tissues, and three-dimensional descriptions of the movement patterns of the wing. A detailed computer model will be constructed, and then used to generate information about the forces developed at the wing joints, the stresses in the wing bones and skin, the mechanical power of flight, the ability of the bones to withstand buckling, and the stability and maneuverability of the wing. Sensitivity analyses will be carried out to determine the relative influence of body size, wing shape, flight speed, and biomechanical properties on the model outputs. The results of this study will be able to serve as the foundation for future studies concerning the origin, diversity, and adaptation of flight among bats.