Results 21 to 30 of about 8,192 (169)
Design and Simulation of Contact Fatigue Testing System of Flexspline and Circular Spline in Harmonic Drive [PDF]
谐波齿轮传动是随着空间技术的发展而诞生的一种新型传动方式,其工作原理是利用柔轮的弹性变形波来实现运动或者动力传递,因其具有结构简单、传动精度高、传动比大等诸多优点,在航空、航天、机器人等领域得到了广泛应用。在谐波齿轮传动过程中,柔轮的运动情况比较复杂,作为弹性薄壁构件需承载交变应力,容易造成齿面磨损和疲劳断裂。因此,建立合适的模型对谐波齿轮传动过程中柔轮的错齿运动进行模拟分析具有重要意义。 本文首先针对谐波齿轮传动过程中柔轮的错齿运动设计了一种新的接触疲劳试验装置 ...
吴泽林
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ABSTRACT Tungsten is inherently brittle and particularly prone to thermal stress concentration and crack formation during additive manufacturing processes such as laser cladding, which severely limits its engineering applications as a coating material. To address this issue, this study proposes an in situ toughening strategy involving the introduction ...
Guo‐Xing Chen +12 more
wiley +1 more source
Behavior of a Flexspline in Harmonic Drive [PDF]
谐波齿轮传动是利用柔性工作构件的弹性变形波进行运动或者动力传递的一种新型传动方式,因其具有体积小、重量轻、精度高、单级传动比大、承载能力高等诸多优点,在航空航天、机器人、数控机床等领域得到了广泛的应用。柔轮作为谐波齿轮传动的关键构件很大程度上影响了谐波齿轮传动的承载能力、使用寿命等。柔轮为弹性薄壁件,在交变载荷作用下易导致齿面磨损和疲劳断裂。柔轮强度、变形与应力分析对谐波齿轮传动过程中的疲劳断裂评估及传动性能研究具有重要的意义。 本文首先根据已知参数、实际工况和谐波齿轮传动啮合参数选取原则 ...
刘淳剑
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Abstract Henry George advocated for capturing land value increases for public ends. The active approach of public authorities organizing and financing land development can help capture higher land value increases, as Hartman and Spit indicate. However, this approach hardly happens in developing countries, where the coalition of private developers and ...
Nannan Xu
wiley +1 more source
Research on Eddy Current Testing of Damages in Carbon Fiber Reinforced Polymers [PDF]
碳纤维增强树脂基复合材料因其优异的性能已被广泛应用于飞行器制造、汽车制造、化学工业、造船与电气设备等各个行业,尤其是在航空航天、船舰以及核能设备等领域受到高度重视。然而,复合材料结构件在制造和使用过程中不可避免的会因为冲击等原因产生各种类型的缺陷。此外,复合材料结构件在损坏之前几乎没有先兆,其破坏具有突然性,这一点往往造成严重的后果。因此对碳纤维增强树脂基复合材料损伤的无损检测研究具有极其重要的意义。 目前应用较多的检测碳纤维增强树脂基复合材料损伤的方法有红外检测、X射线检测以及超声检测等 ...
杜飞
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ABSTRACT Despite the efforts devoted to improving L2 writing pedagogy to promote student writing development, students’ dissatisfactory writing development and outcomes are still reported. Investigating student learning preparedness to navigate L2 writing curriculum transitions may generate new understandings and provide an alternative explanation for ...
Yu Zhou, Shulin Yu
wiley +1 more source
Research on Structural Design and Mechanical Behavior of Double Arc Tooth Profile Harmonic Drive [PDF]
谐波齿轮减速器是一种传动精度高、减速比大并能够在密闭空间传动的齿轮传动机构,应用领域广泛,尤其在航空航天领域有不可替代的优势。常用的渐开线齿廓齿根处会出现应力集中以及齿顶产生尖点啮合现象,影响其承载性能和啮合质量。双圆弧齿形谐波齿轮以其良好的承载能力与啮合性能逐渐成为研究热点,本文根据谐波齿轮设计理论设计了双圆弧谐波齿轮装置,并对其结构性能、接触特性以及动力学等方面的分析,探索相关规律,为后续在结构优化、增强啮合性能提供了一定的理论依据。 论文主要包括以下几方面内容: 1 ...
王萌萌
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Using online reports of seahorse seizures to track their illegal trade
Abstract Illegal wildlife trade (IWT) is a persistent and extensive threat to global biodiversity. Hundreds of marine fish species are subject to regulation under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), but it is unclear how much protection species gain from CITES because information on marine fish ...
Sarah J. Foster +3 more
wiley +1 more source
Crack propagation is one of the key issues for simulating nonlinear behavior and evaluating safety of concrete structures. The equivalent crack opening displacement of smeared damage-fracture model is formulated with damage parameter and crack band width.
Long, Y, Zhang, C, Zhou, Y
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ABSTRACT Policy evaluation is crucial for effective governance and development in the Global South, yet its institutionalization is shaped by a complex interplay of historical, political, and transnational factors. This study examines how colonial legacies, domestic political dynamics, and external influences converge to influence policy evaluation ...
Anis Ben Brik
wiley +1 more source

