Aircraft Engineering and Aerospace Technology ( IF 1.5 ) Pub Date : 2020-07-01 , DOI: 10.1108/aeat-01-2020-0007 Anil Kumar Agrawal , Mahendra Pratap , Subhash Chandra Sati , Rajeev Kumar Upadhyay
Purpose
The purpose of this paper is to optimize the design of a hybrid tether using probabilistic approach considering inherent random variation in the stress developed and the strength it has. The variation in strength is mostly because of variation in diameter of the tether and the properties of the material along the length of the tether. As a result, classical design approach for the tether may not serve the purpose. For this purpose, a reliability-based design of hybrid tether is discussed in this paper.
Design/methodology/approach
A literature review was carried out on the design of tether and its operational reliability. It has been shown that the classical design approach does not serve the purpose, as the strategic operation has to be reliable enough, often requiring a measure of reliability required. A reliability-based approach has been presented to achieve the optimum design of a hybrid tether.
Findings
The optimization problem was carried out for different values of the safety factor to investigate the effect on the optimal design of tether. An analysis is carried out to show that one should not target a very high value of reliability or factor of safety, as it causes the self-weight of the tether to increase tremendously and its cost significantly.
Research limitations/implications
The present work has been carried out considering the limited data and can further be extended to determine more accurate reliability measures by considering more number of sample test data. The measured data is collected from limited required trials for demo; do not represent the exact population data.
Originality/value
Lab strength test and flight trials were conducted to acquire data for the present analysis. In field use, it was noticed that the tether degraded from top portion attached toward the balloon end because of maximum exposure and repeated usage.
中文翻译:
基于可靠性的混合链优化设计
目的
本文的目的是考虑到所产生的应力及其所具有的强度固有的随机变化,使用概率方法来优化混合系绳的设计。强度的变化主要是由于系绳直径的变化以及沿着系绳长度的材料特性所致。结果,用于系绳的经典设计方法可能无法达到目的。为此,本文讨论了基于可靠性的混合系绳设计。
设计/方法/方法
对系绳的设计及其操作可靠性进行了文献综述。已经表明,经典的设计方法不能达到目的,因为战略操作必须足够可靠,常常需要一定程度的可靠性。已经提出了一种基于可靠性的方法来实现混合系绳的最佳设计。
发现
针对不同的安全系数值进行了优化,以研究其对系链优化设计的影响。进行的一项分析表明,不应将可靠性或安全性因素的价值提高到很高的水平,因为这会导致系绳的自重急剧增加且成本显着增加。
研究局限/意义
目前的工作是在考虑有限数据的情况下进行的,并且可以通过考虑更多数量的样本测试数据来进一步扩展,以确定更准确的可靠性措施。测量的数据是从有限的必需试验中收集的,以进行演示;不代表确切的人口数据。
创意/价值
进行了实验室强度测试和飞行试验,以获取本分析所需的数据。在野外使用中,由于最大的暴露和重复使用,注意到系绳从附接的顶部朝向球囊末端降解。