IN-VIVO STRAIN IN THE HUMERUS OF PIGEONS (COLUMBA-LIVIA) DURING FLIGHT
IN-VIVO STRAIN IN THE HUMERUS OF PIGEONS (COLUMBA-LIVIA) DURING FLIGHT
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DOI：
10.1002/jmor.1052250106
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发表时间：
1995-07-01
影响因子：
1.5
通讯作者：
DIAL, KP
中科院分区：
文献类型：
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作者：
BIEWENER, AA;DIAL, KP
纵向和主应变记录在体内在三个地点（背侧，前，腹侧）的肱骨中段的鸽子执行五种模式的自由飞行：起飞，水平飞行，着陆，垂直上升，近垂直下降。当鸟类飞行时携带的重量为其体重的33%、50%或100%时，也记录了菌株。在所有飞行模式下，在三个表面中轴部位和整个骨皮质测得的应变的相对分布相似。在背侧和腹侧肱骨记录的主要应变表明，相当大的扭转所产生的空气动力学负荷的翼面后面的骨头。测得的扭转剪切应变（最大值：平飞时2，700 - 4，150 μ m）比纵向应变大1.5倍。除了扭转，肱骨也受到显着的背腹弯曲，由于升力作用在机翼在下降行程。在肱骨干皮质纵向应变的横截面分布的分析表明，弯曲的方向转移在一个规则的方式在下冲程，表明机翼产生越来越多的推力（与电梯）后，在下冲程。在需要更大升力的起飞和垂直上升过程中，这种偏移较小。从着陆到垂直上升飞行和起飞，峰值主应变和纵向应变平均仅增加50%（例如，肱骨背侧：-1，503至-2，329亩），在任何地点都不超过-2，600亩，即使鸟类飞行时携带两倍体重。当鸟类以两倍于其体重（100%BW负荷）的速度飞行时记录的应变与垂直上升和起飞期间记录的应变在幅度上相似，并且可能代表最大性能期间开发的应变。在中轴内开发的应变是最大的前背侧和后腹侧皮质，而不是在背侧，腹侧和前部的网站在应变记录。因此，骨所经历的最大应变可能比记录的应变大20-25%（约20%）。3，200 μ m），表明压缩应变破坏的安全系数约为3.5。然而，更高的剪切应变表明安全系数较低（1.9），其中骨的扭转强度是其最关键的设计特征。最后，鸽子肱骨中的应变的大小和分布通常与飞行期间大型食果蝙蝠肱骨中记录的应变相似。(C)1995年Wiley-Liss，Inc.
Longitudinal and principal strain recordings were made in vivo at three sites (dorsal, anterior, and ventral) on the humeral midshaft of pigeons executing five modes of free flight: take-off, level flight, landing, vertical ascent, and near-vertical descent. Strains were also recorded while the birds flew carrying weights that were 33%, 50%, or 100% of their body weight. The relative distribution of strain measured at the three surface midshaft sites and across the bone's cortex was found to be similar for all flight modes. Principal strains recorded in the dorsal and ventral humerus indicated considerable torsion produced by aerodynamic loading of the wing surface posterior to the bone. Measured torsional shear strains (maximum: 2,700-4,150 mu epsilon during level flight) were 1.5 times greater than longitudinal strains. In addition to torsion, the humerus is also subjected to significant dorsoventral bending owing to lift forces acting on the wing during the downstroke. Analysis of the cross-sectional distribution of longitudinal strains at the humeral midshaft cortex shows that the orientation of bending shifts in a regular manner during the downstroke, indicating that the wing generates progressively more thrust (vs. lift) later in the downstroke. This shift is less during take-off and vertical ascent when greater lift is required. Peak principal and longitudinal strains increased by an average of only 50% from landing to vertical ascending flight and take-off (e.g., dorsal humerus: -1,503 to -2,329 mu epsilon) and did not exceed -2,600 mu epsilon at any site, even when the birds flew carrying twice their body weight. Strains recorded when birds flew at two times their body weight (100% BW load) were similar in magnitude to those recorded during vertical ascent and take-off and likely represent those developed during maximal performance. Strains developed within the midshaft were maximal in the anterodorsal and posteroventral cortices, not at the dorsal, ventral, and anterior sites at which strain was recorded. Consequently, maximum strains experienced by the bone are probably 20-25% greater than those recorded (ca. 3,200 mu epsilon), indicating a safety factor of about 3.5 for compressive strain failure. The much higher shear strains, however, indicate a lower safety factor (1.9), in which the bone's torsional strength is its most critical design feature. Finally, the magnitude and distribution of strains developed in the humerus of pigeons are generally similar to those recorded in the humerus of large fruit-eating bats during flight. (C) 1995 Wiley-Liss, Inc.