Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 7Citation - Scopus: 7A Comprehensive Study on Burst Pressure Performance of Aluminum Liner for Hydrogen Storage Vessels(ASME, 2021) Kangal, Serkan; Sayı, Abdülmecit Harun; Ayakdaş, Ozan; Kartav, Osman; Aydın, Levent; Artem, Hatice Seçil; Aktaş, Engin; Yücetürk, Kutay; Tanoğlu, Metin; Kandemir, Sinan; Beylergil, BertanThis paper presents a comparative study on the burst pressure performance of aluminum (Al) liner for type-III composite overwrapped pressure vessels (COPVs). In the analysis, the vessels were loaded with increasing internal pressure up to the burst pressure level. In the analytical part of the study, the burst pressure of the cylindrical part was predicted based on the modified von Mises, Tresca, and average shear stress criterion (ASSC). In the numerical analysis, a finite element (FE) model was established in order to predict the behavior of the vessel as a function of increasing internal pressure and determine the final burst. The Al pressure vessels made of Al-6061-T6 alloy with a capacity of 5 L were designed. The manufacturing of the metallic vessels was purchased from a metal forming company. The experimental study was conducted by pressurizing the Al vessels until the burst failure occurred. The radial and axial strain behaviors were monitored at various locations on the vessels during loading. The results obtained through analytical, numerical, and experimental work were compared. The average experimental burst pressure of the vessels was found to be 279 bar. The experimental strain data were compared with the results of the FE analysis. The results indicated that the FE analysis and ASSC-based elastoplastic analytical approaches yielded the best predictions which are within 2.2% of the experimental burst failure values. It was also found that the elastic analysis underestimated the burst failure results; however, it was effective for determining the critical regions over the vessel structure. The strain behavior of the vessels obtained through experimental investigations was well correlated with those predicted through FE analysis.Article Citation - WoS: 7Citation - Scopus: 7Merging Tree Algorithm of Growing Voids in Self-Similar and Cdm Models(Oxford University Press, 2013) Russell, EsraObservational studies show that voids are prominent features of the large-scale structure of the present-day Universe. Even though their emerging from the primordial density perturbations and evolutionary patterns differ from dark matter haloes, N-body simulations and theoretical models have shown that voids also merge together to form large void structures. In this study, following Sheth & van de Weygaert, we formulate an analytical approximate description of the hierarchical void evolution of growing voids by adopting the halo merging algorithm given by Lacey & Cole in the Einstein de Sitter (EdS) Universe. To do this, we take into account the general volume distribution of voids which consists of two main void processes: merging and collapsing.We show that the volume distribution function can be reduced to a simple form, by neglecting the collapsing void contribution since the collapse process is negligible for largesize voids. Therefore, the void volume fraction has a contribution only from growing voids. This algorithm becomes the analogue of the halo merging algorithm. Based on this growing void distribution, we obtain the void merging algorithm in which we define and formulate void merging and absorption rates, as well as void size and redshift survival probabilities and also failure rates in terms of the self-similar and currently favoured dark-energy-dominated cold dark matter models in the EdS Universe.