International Journal of Protective Structures最新文献

{"title":"Dynamic response and safety control of civil air defense tunnel group during the whole process of underpass tunnel blasting excavation","authors":"Fengjiao Yang, N. Jiang, Chuan-bo Zhou, Guopeng Lyu, Yingkang Yao","doi":"10.1177/20414196221119234","DOIUrl":"https://doi.org/10.1177/20414196221119234","url":null,"abstract":"To ensure the safety and stability of adjacent underground structures is a key problem for the subway tunnel blasting construction. In this paper, there is a tunnel group (Sheshan civil air defense engineering) composed of several tunnel units right above a subway tunnel under blasting construction (Wuhan Metro Line 5). The vibration of the tunnel group induced by two blasting excavations of the subway tunnel was monitored. For further research, an effective 3D numerical model established by LS-DYNA, which was verified by field monitoring data, was used to analyze the dynamic response of the tunnel group in the whole process of the subway tunnel blasting. According to the numerical simulation results, the dynamic response characteristics of each tunnel unit were studied, and the most vulnerable area in each tunnel unit was determined. Then, the functional relationships between the maximum vibration velocities and the maximum tensile stresses of the vulnerable areas were established. Based on the maximum tensile stress criterion, the safety vibration velocity threshold of each vulnerable area was calculated using the relationship models. Furthermore, for convenient field monitoring during the subway construction, the safety vibration threshold at the floor of the tunnel group was also calculated. Lastly, to obtain the maximum charge per delay, five cut blasting with different charges were simulated. The maximum charge of the cut blasting in different stages of the subway tunnel blasting excavation was proposed. The research results of this paper have reference value for the blasting vibration safety control of similar tunnel excavation projects in the future.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48812687","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":"The dynamic material properties of stabilised rammed earth materials using cement and calcium carbonate residue","authors":"Ke-wei Liu, M. Walske, Minbo Zhou, Xihong Zhang","doi":"10.1177/20414196221119239","DOIUrl":"https://doi.org/10.1177/20414196221119239","url":null,"abstract":"The use of rammed earth (RE) as a construction material has recently received renewed interest due to its sustainability characteristics and potential for low-cost construction. Modern RE includes the addition of a binder to increase its performance. The mechanical performance of stabilised RE particularly the dynamic material properties is still not well understood. During the design life, a structure could experience dynamic loading. It is necessary to properly understand the dynamic properties of stabilised RE for safe applications. In this study, the quasi-static and dynamic material properties of cement and calcium carbonate residue (CCR) stabilised RE are experimentally investigated. The failure of the stabilised RE under different loading rates is investigated. Dynamic increase effect on cement and CCR stabilised RE are studied. The unconfined uniaxial compressive strength (UCS), Young’s modulus of the two types of stabilised RE at different strain rates are quantified. Empirical formulae of dynamic increase factor are derived for engineering application.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48251776","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 on dynamic compressive and splitting tensile properties of high strength expansive concrete","authors":"Qiyao Li, Li Chen, Chengjun Yue, Yuzhou Zheng, Jiayi Yuan, Xudong Chen","doi":"10.1177/20414196221119232","DOIUrl":"https://doi.org/10.1177/20414196221119232","url":null,"abstract":"Concrete shrinkage usually results in the decrease in bearing capacity, durability and impact resistance of Concrete-Filled steel tube (CFST) structures during its service life. High strength expansive concrete (HSEC) is recently developed to deal with the shrinkage cracking in CFST structures. In this study, dynamic compressive tests and dynamic splitting tensile tests on the developed grade C60, C70 and C80 HSEC were performed using a split Hopkinson pressure bar device. Test results show that the expansive concrete is a typical rate-sensitive material, and its dynamic compressive strength and dynamic splitting tensile strength both increase with the strain rate. The compressive strength dynamic increase factor (DIFc) of HSEC is smaller than that of the ordinary concrete under the same strain rate, whereas the splitting tensile dynamic increase factor (DIFt) is larger than that of the ordinary concrete. All the test data were classified to establish calculation models of DIFc, peak toughness ( Rp), specific energy absorption (SEA), and DIFt, which provide a theoretical basis for the design and application of HSEC and CFST in engineering.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45299261","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":"Evaluation of shock wave properties interacting with a parallelepipedal obstacle","authors":"Antoine Gautier, I. Sochet, Sébastion Courtiaud, E. Lapebie","doi":"10.1177/20414196221114908","DOIUrl":"https://doi.org/10.1177/20414196221114908","url":null,"abstract":"The aim of this study was to characterize the interaction of a shock wave with a parallelepipedal obstacle. Shock wave properties were quantified downstream of sixty configurations with different obstacle dimensions. With the introduction of new parameters, these experimental measurements were used to write evolution laws for the arrival time and the maximum overpressure downstream of a parallelepipedal obstacle. The accuracy of these laws was satisfactory. Then, the maximum overpressure law was compared with experimental measures from the literature. Despite differences in the obstacle geometry or experimental setup, these experimental data are in good agreement with the maximum overpressure law.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45538452","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":"Assessing the stab resistive performance of material extruded body armour specimens","authors":"U. I. Cicek, D. Southee, A. Johnson","doi":"10.1177/20414196221112148","DOIUrl":"https://doi.org/10.1177/20414196221112148","url":null,"abstract":"This paper investigates the effect of material extruded body armour specimen size on stab penetration depth and back-face signature (BFS) and establishes the minimum thickness required for a series of material extrusion materials to provide protection against the UK Home Office Scientific Development Branch (HOSDB) body armour KR1-E1 requirements. In stage one, material extruded planar test specimens ranging from 40 × 40 mm to 80 × 80 mm in length and width with 10 mm increments at three different thicknesses, 6, 8 and 10 mm, were stab tested under 24 joules of impact energy using a gravity driven drop test apparatus. In stage two, 50 × 50 mm specimens in six material categories, PC, ABS, PLA, TPLA, PA and TPU, were manufactured at different thicknesses via material extrusion and impacted in accordance with the UK HOSDB KR1-E1 stab impact energy level as they were the optimum size when considering overall stab and BFS performance. The study established the fundamental steps towards the use of material extrusion in future personal protection solutions. Results demonstrated that stab penetration and BFS were dependent on specimen size, thickness and material type, and there was an inverse relationship between stab penetration depth and BFS. Also, a minimum thickness of 5 mm for PC and TPLA, 6 mm for ABS, 7 mm for PLA, 11 mm for PA and 12 mm for TPU, with 100% print density, was required in order to provide protection against the HOSDB KR1-E1 level of 24 J stab impact energy.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41398018","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":"Blast resistance of timber structural elements: A state-of-the-art review","authors":"R. Mourão, A. Caçoilo, F. Teixeira-Dias, A. Montalva, Hollice F. Stone, Eric Jacques","doi":"10.1177/20414196221092466","DOIUrl":"https://doi.org/10.1177/20414196221092466","url":null,"abstract":"The response of structures subject to impulsive loads remains a field of intense research. Whilst traditional construction materials, such as steel and concrete/masonry, have been the focus of most studies, further research on the performance of alternative materials for blast-resistant applications has been driven by their growing use in sustainable construction. Over the last years, engineers have been re-evaluating the use of timber as a prime construction material for a range of building types, from small office to high-rise residential buildings. As a result, there is now a growing need to study the blast resistance of timber structures, as they may become potential targets of terrorist attacks or being placed in the blast-radius of other critical buildings. A review of existing research on the blast resistance of timber structures is presented and key factors on the blast analysis and design of such structures are discussed. Most of the research has been conducted on light-frame wood stud walls, glued- and cross-laminated timber, and addresses material properties under high strain rates, typical failure modes, behaviour of structural connections and retrofitting solutions. Failure modes are reported to be highly dependent on the element layout and manufacturing aspects, and dynamic increase factors for the modulus of elasticity and maximum strength in the ranges of [1.05, 1.43] and [1.14, 1.60], respectively, have been proposed for different timber elements. Mechanical connectors play a significant role in dissipating energy through plastic deformation, as the brittle nature of timber elements compromises the development of their full capacity. Regardless the element type, SDOF models can accurately predict the dynamic response as long as idealised boundary conditions can be considered. Overall, although a good amount of research is available, more extensive research is needed to guide the design and engineering practice and contribute to the development of design codes and testing standards for timber structures under blast loading.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47108202","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":"Crashworthiness investigation of draw bead in aluminum tubes under axial loading condition","authors":"H. Nikkhah, N. Naveed, Roghaiyeh Assaedi Beiragh, Sina Dadashzadeh, Q. Truong","doi":"10.1177/20414196221090989","DOIUrl":"https://doi.org/10.1177/20414196221090989","url":null,"abstract":"This study aims to investigate the effects of the draw beads on the crashworthiness of the aluminum tubes under axial quasi-static loading. Based on this design philosophy, a total of 12 beading tube designs with various configurations were developed. Within each design, the effect of arrangement bead form on the crashworthiness performance was also analyzed. A finite element model, validated using experimental tests, was used to study the crashworthiness performance and progressive deformation of the tubes. Based on the results, a multi-criteria decision-making method known as Technique of Order Preference by Similarity to Ideal Solution was employed to determine the most suitable tube that features high energy absorption and low impact force. The best tube with a high score was selected to investigate the effect of bead formed direction on aluminum tubes. Consequently, the study identified a bead shape tubes configuration that exhibits superior crashworthiness and low impact force. The beading tube design methodology presented in this study allows the exploitation of variable shapes geometries for the development of high-efficiency energy-absorbing structures and their crushing behaviors.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41657252","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":"More on the penetration of spherical-nosed rigid projectiles into metallic targets","authors":"Y. Vayig, Z. Rosenberg, D. Ornai","doi":"10.1177/20414196221092475","DOIUrl":"https://doi.org/10.1177/20414196221092475","url":null,"abstract":"This work deals with several issues related to the deep penetration of spherically nosed rigid projectiles impacting metallic targets at normal incidence. The most important issues in these processes are the constant resisting stress acting on the projectile beyond the initial entrance phase, the extent of the entrance phase, and the onset of cavitation at impact velocities higher than a certain threshold velocity. In this work, we derive a new relation for the target’s resisting stress in terms of its bulk and shear moduli and we also use a simplified analysis to account for the effect of the entrance phase on the depth of penetration for spherically nosed rigid projectiles. In addition, we highlight the role of cavitation in this process through numerical simulations for targets having very different densities.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45997400","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":"An experimental and simulated investigation into the validity of unrestricted blast wave scaling models when applied to transonic flow in complex tunnel environments","authors":"Emily M. Johnson, N. Grahl, M. Langenderfer, David Doucet, Joseph Schott, K. Williams, B. Rutter, Catherine E. Johnson","doi":"10.1177/20414196221095252","DOIUrl":"https://doi.org/10.1177/20414196221095252","url":null,"abstract":"Since the inception of high explosives as an industrial tool, significant efforts have been made to understand the flow of energy from an explosive into its surroundings to maximize work produced while minimizing damaging effects. Many tools have been developed over the past century, such as the Hopkinson–Cranz (H-C) Scaling Formula, to define blast wave behavior in open air. Despite these efforts, the complexity of wave dynamics has rendered blast wave prediction difficult under confinement, where the wave interacts with reflective surfaces producing complex time-pressure waveforms. This paper implements two methods to better understand blast overpressure propagation in a confined tunnel environment and establish whether scaled tests can be performed comparatively to costly full-scale experiments. Time–pressure waveforms were predicted using both a 1:10 scaled model and three-dimensional air blast simulations conducted in Ansys Autodyn. A comparison of the reduced scale model simulation with a full-scale blast simulation resulted in self-similar overpressure waveforms when employing the H-C scaling model. Experimental overpressure waveforms showed a high level of correlation between the reduced scale model and simulations. Additionally, peak overpressure, duration, and impulse values were found to match within tolerances that are highly promising for applying this methodology in future applications. Using this validated relationship, the simulated model and reduced scale tests were used to predict an overpressure waveform in a full-scale underground mine opening to within 2.12%, 2.91%, and 7.84% for peak overpressure, time of arrival, and impulse, respectively. This paper demonstrates the effectiveness of scaled, blast models when predicting blast wave parameters in a confined environment.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41632756","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":"Deformation and failure of thin domed-scored metallic disc under impulsive loading","authors":"Gopinath Kanakadandi, V. Narayanamurthy, Y. Rao","doi":"10.1177/20414196221095249","DOIUrl":"https://doi.org/10.1177/20414196221095249","url":null,"abstract":"This paper presents the structural deformation and failure of a thin domed-scored metallic disc (SMD) applied at the bottom of a pressurized rocket silo which needs to withstand a storage pressure and undergo instantaneous rupture under an impulsive pressure. Initially, the large deformation and rupture of a flat-thin SMD subjected to a pressure impulse is numerically studied and validated with experimental results. Subsequently, the behavior of a domed-thin SMD is investigated for the aforementioned loadings in the rocket silo. The influence of loading rates ( P · ) , score depth and width-to-disc thickness ratio (t 1 /t and b/t), diameter-to-disc thickness ratio (D/t), dome height-to-disc diameter ratio (H/D), score length-to-disc radius ratio (l/R), score pattern, and score geometry on the deformation and failure response of the domed-thin SMD is investigated. The studies demonstrate that (1) the failure initiation point shifts from 1/4th radius to the disc center for loading rates > 10 MPa/s; (2) under impulse loading, the responses are (i) sensitive to the loading rates up to 100 MPa/s, (ii) sensitive to score’s depth, only up to half the disc thickness and insensitive to score’s width, (iii) unaffected for number of scores N > 6, (iv) stabilized for l/R > 0.4, and (vii) almost the same for semi-circular, rectangular and triangular score geometries; (3) the failure do not initiate and propagate along all scores for N > 10 in the disc; and (4) behavior of the domed SMD approaches to that of a spherical dome for H/D > 0.3.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45452899","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}