http://yetl.yabesh.ir/yetl1/handle/yetl/19038 Sat, 23 May 2026 17:31:35 GMT 2026-05-23T17:31:35Z http://localhost:80/yetl1/bitstream/id/436500/ http://yetl.yabesh.ir/yetl1/handle/yetl/19038 http://yetl.yabesh.ir/yetl1/handle/yetl/4308778 The Influence of Headform Pose on the Blunt Impact Performance of American Football Helmets Jesunathadas, Mark; Edwards, Elizabeth D.; Landry, Tiffany L.; Piland, Scott G.; Gould, Trenton E.; Plaisted, Thomas A. The purpose of this research was to evaluate the influence of anthropomorphic test device (ATD) head–neck system pose on the kinematic responses of an ATD donning football helmets during blunt impact tests. Specifically, for two American football helmets, we aimed to determine if identical impact locations but with two different ATD head–neck poses resulted in differences in ATD headform kinematics. Eight Xenith Shadow and eight X2E+ American football helmets were fit to a medium National Operating Committee of Standards for Athletic Equipment (NOCSAE) ATD attached to a male 50th percentile Hybrid III neck. Each helmet was impacted at 6 m/s using a pneumatic linear ram four times at four sites on the helmet. One set (four) of the Shadow and (four) X2E+ helmets were impacted with the ATD head–neck mount system rotated in a manner that sometimes resulted in a flexed looking pose (flexed pose). The other set (four Shadow and four X2E+) were impacted with the ATD head–neck mount system rotated in a manner that sometimes resulted in a lateral bending type pose (lateral bending pose). Dependent measures included the difference (d) between the two poses (flexion–lateral bending) in peak linear acceleration (dPLA), peak angular acceleration (dPAA), and peak angular velocity (dPAV). A significant interaction between helmet and location was observed for dPLA (p < 0.001), dPAA (p < 0.001), and dPAV (p < 0.001). A main effect for helmet was also observed for dPLA (p < 0.001), dPAA (p = 0.025), and dPAV (p < 0.008). The effect of such results within the context of methodologies that rank helmets according to blunt impact performance is discussed. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4308778 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4308774 Wearable Tensiometry for Measuring Achilles and Patellar Tendon Loading While Walking on Various Terrains and Stairs Reiter, Alex J.; Schmida, Elizabeth A.; Ma, Yiteng; Adamczyk, Peter G.; Thelen, Darryl G. - Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4308774 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4308712 A Multichamber Pulsating-Flow Device With Optimized Spatial Shear Stress and Pressure for Endothelial Cell Testing Campos, Obed A.; Garcia-Herreros, Antoni; Sánchez, Antonio L.; Fineman, Jeffrey R.; Pawlak, Geno Design and analysis are presented for a new device to test the response of endothelial cells to the simultaneous action of cyclic shear stresses and pressure fluctuations. The design consists of four pulsatile-flow chambers connected in series, where shear stress is identical in all four chambers and pressure amplitude decreases in successive chambers. Each flow chamber is bounded above and below by two parallel plates separated by a small gap. The design of the chamber planform must ensure that cells within the testing region experience spatially uniform time-periodic shear stress. For conditions typically encountered in applications, the viscous unsteady flow exhibits order-unity values of the associated Womersley number. The corresponding solution to the unsteady lubrication problem, with general nonsinusoidal flowrate, is formulated in terms of a stream function satisfying Laplace's equation, which can be integrated numerically to determine the spatial distribution of shear stresses for chambers of general planform. The results are used to optimize the design of a device with a hexagonal planform. Accompanying experiments using particle tracking velocimetry (PTV) in a fabricated chamber were conducted to validate theoretical predictions. Pressure readings indicate that intrachamber pressure variations associated with viscous pressure losses and acoustic fluctuations are relatively small, so that all cells in a given testing region experience nearly equal pressure forces. Mon, 01 Jan 2024 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4308712 2024-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4308680 Personalized Parameter Setting in Musculoskeletal Models Through Multitrajectory Optimization Jiang, Po-Hsien; Lin, Yi-Hsuan; Wang, Shiu-Min; Hsu, Wei-Li; Chan, Kuei-Yuan - Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4308680 2025-01-01T00:00:00Z