Explosion Shock Waves and High Strain Rate Phenomena最新文献

{"title":"Azimuthal Characteristics on Blast Wave from a Cylindrical Charge – Small Scale Experiment –","authors":"K. Wakabayashi, T. Homae, Y. Sugitana, T. Matsumura","doi":"10.21741/9781644900338-9","DOIUrl":"https://doi.org/10.21741/9781644900338-9","url":null,"abstract":"Azimuthal characteristics on blast wave from a cylindrical charge were experimentally investigated. A cylindrical PETN pellet, weight of 0.50 g, was detonated on a large steel plate, which is a model of the ground surface. 0°was defined as the direction of detonation, which was correspondence with the central symmetry axis of the cylindrical pellet. 12 pressure transducers were embedded in the steel plate to measure the pressure histories on the plate. The direction of the pellet and detonation was rotated every 30° and the distribution of blast pressure histories around the explosive were obtained. The peak overpressure and impulse were high in the range from 30° to 80° compared with the standard explosion data in which the explosive was placed vertically for a two-dimensional axisymmetric explosion on the steel plate and detonated from the top of the explosive. On the contrary, these blast parameters were low in the range from 90° to 130°. These blast pressures were not low in the direction of 180°. These findings are important for safety. The data will be compared with numerical simulations in future. Introduction Explosion of non-spherical explosive causes anisotropic blast wave. This anisotropic blast waves have been extensively studied for many decades. Especially, explosion of cylindrical explosive, which is relatively symmetric, have been studied both experimentally and numerically. R.A. Strehlow and W.E. Baker reviewed these studies in 1976 [1]. As the experimental technique and numerical analysis technique have been improving, many papers have been published until present [2]. It is noteworthy for safety that the blast wave in specific direction is reported to be strong in these papers. The authors carried out indoor tabletop experiments for evaluating the blast wave, using explosive of 1 g scale, and the obtained data were examined by numerical analysis. The authors reported the blast wave mitigation or distribution in a couple of systems [3-6]. In this study, the authors applied the technique above to evaluate the blast wave distribution from a cylindrical explosive precisely. The experimental system was designed under consideration for numerical analysis. Experiment Test Explosives. A PETN pellet, weight of 0.50 g, was used as a test explosive. Its length and diameter were both 7.5 mm. It contained 5 wt% of carbon for forming. A specially designed electric detonator with 100 mg lead azide was used as a detonator. Both the PETN pellet and the Explosion Shock Waves and High Strain Rate Phenomena Materials Research Forum LLC Materials Research Proceedings 13 (2019) 53-56 https://doi.org/10.21741/9781644900338-9 54 detonator were distributed by Showa Kinzoku Kogyo Co. Ltd. A spacer was used so as to the height of the center of the explosive was 0.18 m/kg.The scaled height was set up as the samescaled height of previous study [5] for comparison. The spacer was made of pasteboard and was rectangular block with the height of 10 mm and base ","PeriodicalId":415881,"journal":{"name":"Explosion Shock Waves and High Strain Rate Phenomena","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128122359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructural and Mechanical Properties of Al 5052-SS 316 Explosive Clads with Different Interlayer","authors":"E. Elango, S. Saravanan, K. Raghukandan","doi":"10.21741/9781644900338-28","DOIUrl":"https://doi.org/10.21741/9781644900338-28","url":null,"abstract":"","PeriodicalId":415881,"journal":{"name":"Explosion Shock Waves and High Strain Rate Phenomena","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129796852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shock Synthesis of Gd2Zr2O7","authors":"T. Sekine, Q. Zhou, P. Chen, Z. Tan, H. Ran, J. Liu","doi":"10.21741/9781644900338-5","DOIUrl":"https://doi.org/10.21741/9781644900338-5","url":null,"abstract":"We dealt with shock compression on a composition of Gd2Zr2O7 by explosive-driven flyer impact methods, because Gd2Zr2O7 with rGd/rZr ration of 1.46 lies at the structural boundary between ordered pyrochlore and defect fluorite structures. The results indicate recovered products depend on shock conditions that we need to specify by further study. Introduction Shock compression process provides unique environments for materials synthesis due to not only the realized high pressure and high temperature but also the shock-enhanced kinetics and fast quenching [1]. The process is a time-limited reaction and favors martensitic phase transformation in general. There are many trials to use shock compression techniques for investigation of solid state reactions [2]. The most typical one has been known historically as diamond synthesis, and the process has been developed to optimize the yield of products. Here we report a progress of shock synthesis of oxide compounds using explosive-driven plate impacts. Rare earth pyrochlore compounds of A2B2O7, where A is a rare earth element and B is a tetravalent cation such as Zr and Ti, exhibit several interesting properties for physical, chemical and industrial applications. The pyrochlore structure is known to form if the cation radii ratio (rA/rB) lies in the range 1.46–1.80. However, the fluorite structure is favored with rA/rB below 1.46. The cation radii ratio rA/rB has an important effect on the high pressure structural stability. Gd2Zr2O7 with rA/rB ratio of 1.46 lies at the structural boundary between ordered pyrochlore and defect fluorite. Hence it is expected to show interesting structural behavior as a function of temperature and pressure. We tried to understand the effect of shock compression on Gd2Zr2O7. Among A2B2X7 (X is anion such as O and F) compounds there are three discrete structures of pyroclore, fluorite, and weberite. Their structural relations are based on the fluorite structure (AX2) where each anion is at the center of the cation tetrahedral (A4X) and the lattice is characterized by a lattice constant of a = ~5 Å with Z=1. In pyrochlore structure, different A and B cations make A4X, B4X, and A2B2X, and the lattice is expanded double (a = ~10 Å) and the number of Z=8. Weberite consists of A3BX, AB3X, and A2B2X, with lattice constants of √2a, 2a, and √2a and with Z=4. Therefore, pyrochlore and weberite have their corresponding superlattices in addition to the fluorite structure. Shock compression technique has never been applied to solid-solid reactions in complicate chemical systems to our knowledge. We explore such chemical systems using shock compression techniques. Explosion Shock Waves and High Strain Rate Phenomena Materials Research Forum LLC Materials Research Proceedings 13 (2019) 31-34 https://doi.org/10.21741/9781644900338-5 32 Experimental methods We dealt shock compression on two starting mixtures of a composition Gd2Zr2O7 (powdered mixture of Gd2O3 + 2 ZrO2 and the product heated","PeriodicalId":415881,"journal":{"name":"Explosion Shock Waves and High Strain Rate Phenomena","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122127779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Study for the Tenderness of Meat using Underwater Shock Waves Generation by Wire Electrical Discharges","authors":"A. Takemoto, H. Kawai, T. Watanabe, S. Itho, K. Hokamoto, Y. Higa, O. Higa, K. Shimojima, H. Iyama","doi":"10.21741/9781644900338-6","DOIUrl":"https://doi.org/10.21741/9781644900338-6","url":null,"abstract":"High age of the population advances in the world. The consumption of meat increases. Some methods of softening of edible meat are methods such as electric energy, pressure, heating and biological. The development of the method of the tenderness that is the high efficiency which can apply to the volume of production of the meat is expected. The National Institute of Technology, Okinawa College (OkNCT) has developed a food processing machine that generates underwater shock waves through wire electrical discharge. The machine can be used for sterilization, milling, tenderness, and extraction among others. In this study, we experimentally examined the conditions for food tenderness using pork as the food material in the experiments. The relationship of the tenderness of edible meat measured with a durometer with the number of underwater shock wave generation, and the distance of the shock wave generation point from the edible meat and reflectance backing material were shown experimentally. The prototype design of the pressure vessel for the processing of the meat was shown. The possibility of designing and manufacturing of a pressure vessel according to the required tenderness was shown.","PeriodicalId":415881,"journal":{"name":"Explosion Shock Waves and High Strain Rate Phenomena","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123588195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of Weldability Window for Aluminum-Steel Explosive Cladding","authors":"K. Hokamoto, G. Murugan, S. Saravanan, K. Raghukandan, S. Tanaka","doi":"10.21741/9781644900338-26","DOIUrl":"https://doi.org/10.21741/9781644900338-26","url":null,"abstract":"This study addresses the development of biaxial and triaxial weldability windowan analytical estimation-for determining the nature of interface in aluminum 5052-stainless steel 304 dissimilar explosive cladding. The lower and upper boundaries of the biaxial weldability window are formulated using empirical relations proposed by earlier researchers. The process parameters dynamic bend angle and collision velocity are chosen as ordinates and abscissa respectively. In addition, a triaxial weldability window, comprising of three process parameters viz., flyer plate velocity, collision velocity and dynamic bend angle is also developed. Explosive cladding experiments were conducted by varying the process parameters and the interface microstructure is correlated with the developed weldability windows.","PeriodicalId":415881,"journal":{"name":"Explosion Shock Waves and High Strain Rate Phenomena","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115568499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High Strain Rate Behaviour of Auxetic Cellular Structures","authors":"N. Novak, Z. Ren, Pengwan Chen, B. Guo, K. Hokamoto, M. Vesenjak, Shigeru Tanaka","doi":"10.21741/9781644900338-4","DOIUrl":"https://doi.org/10.21741/9781644900338-4","url":null,"abstract":"Auxetic cellular structures are modern metamaterials with negative Poisson’s ratio. The auxetic cellular structures build from inverted tetrapods were fabricated and experimentally tested under dynamic loading conditions to evaluate the effect of strain rate on their deformation mode. The Split-Hopkinson Pressure Bar (SHPB) apparatus was used for testing at strain rates up to 1,250 s, while a powder gun was used for testing at strain rates up to 5,000 s. The homogeneous deformation mode was observed at lower strain rates, while shock deformation mode was predominant at higher rates. The results have shown that the strain rate hardening of analysed auxetic specimens is prominent at higher strain rates when the shock deformation mode is observed, i.e. when most of deformation occurs at the impact front. Relevant computational models in LS-DYNA were developed and validated. A very good correlation between the computational and experimental data was observed. Introduction Auxetic cellular structures are novel metamaterials with negative Poisson’s ratio – they tend to expand in lateral direction when subjected to tensile loading and vice versa in the case of compression loading [1]. This behaviour can be beneficial in many applications, especially in the crashworthiness, ballistic protection and energy absorption applications [2]. The mechanical behaviour of auxetic structures is well characterised and understood for quasi-static loading conditions, but not so much for dynamic and impact loading due to insufficient experimental characterisation attempts so far. Past studies were mostly concerned with the quasi-static elastic behaviour of uniform auxetic structures at very small strains [3] and limited ballistic resistance study [4]. Mechanical behaviour of some particular auxetic structures was characterised by uniaxial quasi-static compressive and tensile tests [5–10]. The Split-Hopkinson Pressure Bar (SHPB) experiments were also carried out for auxetic cellular structures fabricated with additive manufacturing, including also polymer fillers [11]. There is a clear need to test the auxetic cellular structures also under high strain rate loading conditions to comprehensively evaluate their behaviour also at highly dynamic loading. Especially since there are many applications where these metamaterials can be used efficiently. Explosion Shock Waves and High Strain Rate Phenomena Materials Research Forum LLC Materials Research Proceedings 13 (2019) 25-30 https://doi.org/10.21741/9781644900338-4 26 Specimens fabrication The specimens build from inverted tetrapods were used in this research. Inverted tetrapods (Fig. 1a), are assembled in a particular way to define the geometry of the investigated specimens (Fig. 1b-c). The specimen’s inverted tetrapod dimensions were (Fig. 1a): a = 3.5 mm, h = 3 mm, dh = 0.5 mm, while the circular cross-section diameter of the struts was in range from 0.38 to 0.53, depending on the porosity (Table 1). Two types of specimen","PeriodicalId":415881,"journal":{"name":"Explosion Shock Waves and High Strain Rate Phenomena","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133405430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Pre-Notch on Deformation of Aluminium Square Plate under Free Blast Loading","authors":"Q. Zhou, A. Arab, Y. Guo","doi":"10.21741/9781644900338-19","DOIUrl":"https://doi.org/10.21741/9781644900338-19","url":null,"abstract":"","PeriodicalId":415881,"journal":{"name":"Explosion Shock Waves and High Strain Rate Phenomena","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114700161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}