Pub Date : 2023-01-05DOI: 10.1177/20414196221149752
Dain G. Farrimond, Scott Woolford, A. Tyas, S. Rigby, S. Clarke, A. Barr, M. Whittaker, D. Pope
A significant amount of scientific effort has been dedicated to measuring and understanding the effects of explosions, leading to the development of semi-empirical methods for rapid prediction of blast load parameters. The most well-known of these, termed the Kingery and Bulmash method, makes use of polylogarithmic curves derived from a compilation of medium to large scale experimental tests performed over many decades. However, there is still no general consensus on the accuracy and validity of this approach, despite some researchers reporting consistently high levels of agreement. Further, it is still not known whether blast loading can be considered deterministic, or whether it is intrinsically variable, the extent of this variability, and the range and scales over which these variations are observed. This article critically reviews historic and contemporary blast experiments, including newly generated arena tests with RDX and PETN-based explosives, with a view to demonstrating the accuracy with which blast load parameters can be predicted using semi-empirical approaches.
{"title":"Far-field positive phase blast parameter characterisation of RDX and PETN based explosives","authors":"Dain G. Farrimond, Scott Woolford, A. Tyas, S. Rigby, S. Clarke, A. Barr, M. Whittaker, D. Pope","doi":"10.1177/20414196221149752","DOIUrl":"https://doi.org/10.1177/20414196221149752","url":null,"abstract":"A significant amount of scientific effort has been dedicated to measuring and understanding the effects of explosions, leading to the development of semi-empirical methods for rapid prediction of blast load parameters. The most well-known of these, termed the Kingery and Bulmash method, makes use of polylogarithmic curves derived from a compilation of medium to large scale experimental tests performed over many decades. However, there is still no general consensus on the accuracy and validity of this approach, despite some researchers reporting consistently high levels of agreement. Further, it is still not known whether blast loading can be considered deterministic, or whether it is intrinsically variable, the extent of this variability, and the range and scales over which these variations are observed. This article critically reviews historic and contemporary blast experiments, including newly generated arena tests with RDX and PETN-based explosives, with a view to demonstrating the accuracy with which blast load parameters can be predicted using semi-empirical approaches.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49210058","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}
Pub Date : 2022-12-09DOI: 10.1177/20414196221144066
Obed Samuelraj Isaac, Omar Ghareeb Alshammari, S. Clarke, S. Rigby
Obstacles arranged into a pre-fractal shape (Sierpinski carpet) were tested for their blast attenuation abilities using 250 g PE4 at three different scaled distances ( Z = 1.87, 2.24, 2.99 m/kg1/3). Three pre-fractal iterations were tested, as well as free-field tests for comparative purposes. Reductions in peak overpressure up to 26% and peak specific impulse up to 19% were observed, attributed to a mechanism known as ‘trapping’. This mechanism is characterised by a reduction in the ability of a blast wave to advect downstream, with corresponding increases in pressure observed within the bounds of the pre-fractal obstacle. Attenuation magnitudes and areas of reduced pressure and impulse were found to be drastically different with each pre-fractal iteration, with a transition from shadowing to wave trapping as the obstacles more closely resembled true fractals. A linear dependence on a newly-defined obstruction factor ( OF) was found for arrival time, overpressure and impulse at the sensor locations, suggesting that the attenuation of a pre-fractal obstacle is inherently determinable. The results indicate that the mechanism of blast mitigation of pre-fractal obstacles is fundamentally different from singular or arrays of regular obstacles, and could be exploited further to develop novel protective structures with enhanced blast attenuation.
采用250 g PE4在三种不同的比例距离(Z = 1.87、2.24、2.99 m/kg1/3)下测试了障碍物布置成预分形(Sierpinski地毯)的爆炸衰减能力。测试了三个预分形迭代，以及用于比较目的的自由场测试。由于一种被称为“捕获”的机制，峰值超压降低了26%，峰值比冲降低了19%。这种机制的特点是爆炸波向下游平流的能力降低，在分形前障碍的范围内观察到相应的压力增加。在每次预分形迭代中，衰减幅度和减少的压力和脉冲面积都有很大的不同，随着障碍物更接近真实的分形，从阴影到波捕获的过渡。到达时间、超压和脉冲与新定义的障碍物因子(OF)呈线性关系，表明前分形障碍物的衰减本质上是可确定的。研究结果表明，预分形障碍物的爆破缓解机制与单一或排列规则障碍物有本质区别，可以进一步开发具有增强爆破衰减的新型防护结构。
{"title":"Experimental investigation of blast mitigation of pre-fractal obstacles","authors":"Obed Samuelraj Isaac, Omar Ghareeb Alshammari, S. Clarke, S. Rigby","doi":"10.1177/20414196221144066","DOIUrl":"https://doi.org/10.1177/20414196221144066","url":null,"abstract":"Obstacles arranged into a pre-fractal shape (Sierpinski carpet) were tested for their blast attenuation abilities using 250 g PE4 at three different scaled distances ( Z = 1.87, 2.24, 2.99 m/kg1/3). Three pre-fractal iterations were tested, as well as free-field tests for comparative purposes. Reductions in peak overpressure up to 26% and peak specific impulse up to 19% were observed, attributed to a mechanism known as ‘trapping’. This mechanism is characterised by a reduction in the ability of a blast wave to advect downstream, with corresponding increases in pressure observed within the bounds of the pre-fractal obstacle. Attenuation magnitudes and areas of reduced pressure and impulse were found to be drastically different with each pre-fractal iteration, with a transition from shadowing to wave trapping as the obstacles more closely resembled true fractals. A linear dependence on a newly-defined obstruction factor ( OF) was found for arrival time, overpressure and impulse at the sensor locations, suggesting that the attenuation of a pre-fractal obstacle is inherently determinable. The results indicate that the mechanism of blast mitigation of pre-fractal obstacles is fundamentally different from singular or arrays of regular obstacles, and could be exploited further to develop novel protective structures with enhanced blast attenuation.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":"2 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41285954","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}
Pub Date : 2022-12-06DOI: 10.1177/20414196221144067
M. Zahedi, Shahriar Golchin
Current empirical and semi-empirical based design manuals are restricted to the analysis of simple building configurations against blast loading. Prediction of blast loads for complex geometries is typically carried out with computational fluid dynamics solvers, which are known for their high computational cost. The combination of high-fidelity simulations with machine learning tools may significantly accelerate processing time, but the efficacy of such tools must be investigated. The present study evaluates various machine learning algorithms to predict peak overpressure and impulse on a protruded structure exposed to blast loading. A dataset with over 250,000 data points extracted from ProSAir simulations is used to train, validate, and test the models. Among the machine learning algorithms, gradient boosting models outperformed neural networks, demonstrating high predictive power. These models required significantly less time for hyperparameter optimization, and the randomized search approach achieved relatively similar results to that of grid search. Based on permutation feature importance studies, the protrusion length was considered a significantly more influential parameter in the construction of decision trees than building height.
{"title":"Prediction of blast loading on protruded structures using machine learning methods","authors":"M. Zahedi, Shahriar Golchin","doi":"10.1177/20414196221144067","DOIUrl":"https://doi.org/10.1177/20414196221144067","url":null,"abstract":"Current empirical and semi-empirical based design manuals are restricted to the analysis of simple building configurations against blast loading. Prediction of blast loads for complex geometries is typically carried out with computational fluid dynamics solvers, which are known for their high computational cost. The combination of high-fidelity simulations with machine learning tools may significantly accelerate processing time, but the efficacy of such tools must be investigated. The present study evaluates various machine learning algorithms to predict peak overpressure and impulse on a protruded structure exposed to blast loading. A dataset with over 250,000 data points extracted from ProSAir simulations is used to train, validate, and test the models. Among the machine learning algorithms, gradient boosting models outperformed neural networks, demonstrating high predictive power. These models required significantly less time for hyperparameter optimization, and the randomized search approach achieved relatively similar results to that of grid search. Based on permutation feature importance studies, the protrusion length was considered a significantly more influential parameter in the construction of decision trees than building height.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43954201","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}
Pub Date : 2022-12-01DOI: 10.1177/20414196221075823
P. Silvestri, G. Naselli, E. Cepolina, M. Zoppi
This paper presents the results obtained during an experimental campaign on blast resistant wheels designed for a low-cost demining machine, derived from an agricultural tractor. Such wheels must fulfil two requirements: first, they have to be able to retain their mechanical integrity in case of blast and still work after one or more explosions, in order to be able to drive the machine out of the minefield without human intervention; second, they must reduce as much as possible the amount of energy transferred to the vehicle, to protect the on-board equipment from the effect of the detonation of a landmine. One of the goals of the experimental activity was to compare two wheels characterized by different designs. Mechanical performance and capacity of the wheels to reduce the energy transferred to the vehicle have been assessed to verify whether the wheels were suitable for the task and to identify which wheel performs best. Physical integrity of both wheels was assessed by visual inspection after each explosion. To evaluate the energy transferred to the vehicle, a measurement of the potential energy transferred, by means of a ballistic pendulum, equipped with an encoder, was performed together with a triaxial acceleration measurement in correspondence of the wheel hub. The triaxial accelerometer measurement was then also used to assess the behaviour of the wheels mounted on the vehicle after tests on the ballistic pendulum. Wheel performances have been quantified using specific features and frequency domain functions, related to the damage induced by the vibration at the interface between the hub and the demining machine. The obtained results suggest that the heaviest wheel performs better both in terms of mechanical integrity and of shock response.
{"title":"Shock qualification of low-cost blast resistant wheels by in field tests","authors":"P. Silvestri, G. Naselli, E. Cepolina, M. Zoppi","doi":"10.1177/20414196221075823","DOIUrl":"https://doi.org/10.1177/20414196221075823","url":null,"abstract":"This paper presents the results obtained during an experimental campaign on blast resistant wheels designed for a low-cost demining machine, derived from an agricultural tractor. Such wheels must fulfil two requirements: first, they have to be able to retain their mechanical integrity in case of blast and still work after one or more explosions, in order to be able to drive the machine out of the minefield without human intervention; second, they must reduce as much as possible the amount of energy transferred to the vehicle, to protect the on-board equipment from the effect of the detonation of a landmine. One of the goals of the experimental activity was to compare two wheels characterized by different designs. Mechanical performance and capacity of the wheels to reduce the energy transferred to the vehicle have been assessed to verify whether the wheels were suitable for the task and to identify which wheel performs best. Physical integrity of both wheels was assessed by visual inspection after each explosion. To evaluate the energy transferred to the vehicle, a measurement of the potential energy transferred, by means of a ballistic pendulum, equipped with an encoder, was performed together with a triaxial acceleration measurement in correspondence of the wheel hub. The triaxial accelerometer measurement was then also used to assess the behaviour of the wheels mounted on the vehicle after tests on the ballistic pendulum. Wheel performances have been quantified using specific features and frequency domain functions, related to the damage induced by the vibration at the interface between the hub and the demining machine. The obtained results suggest that the heaviest wheel performs better both in terms of mechanical integrity and of shock response.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":"13 1","pages":"601 - 628"},"PeriodicalIF":2.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66136401","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}
Pub Date : 2022-11-10DOI: 10.1177/20414196221138596
Yeou-Fong Li, G. Ramanathan, Jin-Yuan Syu, Chih-Hong Huang, Ying-Kuan Tsai
Impact and blast wave loadings act as high instant energy and might cause damage to reinforced concrete infrastructures. This research aims to investigate the effect of using different length proportions of carbon fiber on the mechanical behaviors of concrete. Moreover, in this study, original carbon fiber and sizing-removed carbon fiber were added into concrete with different mix-proportions. The sizing on the carbon fiber surface was removed by using heat-treated method. In addition, the carbon fiber was dispersed by a high-pressure air compressor. Lengths of 12 mm and 24 mm carbon fibers were used in different mix-proportions to find the highest mechanical strength of carbon fiber reinforced concrete (CFRC) under a 1% fiber-to-cement weight ratio. Compressive, flexural, and impact tests were conducted on CFRC specimens. The CFRC specimen with 50% 12 mm and 50% 24 mm sizing-removed carbon fiber attained the highest impact resistance, and it also had the best performance under blast wave loading compared with the other CFRC specimens. The broken CFRC specimens were examined by an optical microscope to identify the failure mode of the carbon fibers in CFRC specimens. The addition of 50% 12 mm and 50% 24 mm sizing-removed carbon fiber can significantly improve the compressive and flexural strength of reinforced concrete.
{"title":"Mechanical behavior of different fiber lengths mix-proportions carbon fiber reinforced concrete subjected to static, impact, and blast loading","authors":"Yeou-Fong Li, G. Ramanathan, Jin-Yuan Syu, Chih-Hong Huang, Ying-Kuan Tsai","doi":"10.1177/20414196221138596","DOIUrl":"https://doi.org/10.1177/20414196221138596","url":null,"abstract":"Impact and blast wave loadings act as high instant energy and might cause damage to reinforced concrete infrastructures. This research aims to investigate the effect of using different length proportions of carbon fiber on the mechanical behaviors of concrete. Moreover, in this study, original carbon fiber and sizing-removed carbon fiber were added into concrete with different mix-proportions. The sizing on the carbon fiber surface was removed by using heat-treated method. In addition, the carbon fiber was dispersed by a high-pressure air compressor. Lengths of 12 mm and 24 mm carbon fibers were used in different mix-proportions to find the highest mechanical strength of carbon fiber reinforced concrete (CFRC) under a 1% fiber-to-cement weight ratio. Compressive, flexural, and impact tests were conducted on CFRC specimens. The CFRC specimen with 50% 12 mm and 50% 24 mm sizing-removed carbon fiber attained the highest impact resistance, and it also had the best performance under blast wave loading compared with the other CFRC specimens. The broken CFRC specimens were examined by an optical microscope to identify the failure mode of the carbon fibers in CFRC specimens. The addition of 50% 12 mm and 50% 24 mm sizing-removed carbon fiber can significantly improve the compressive and flexural strength of reinforced concrete.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42215960","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}
Pub Date : 2022-11-01DOI: 10.1177/20414196221137918
G. Ruscade, I. Sochet, K. Djafer
Nowadays, the safety of infrastructure and people is a primary concern. To ensure safety in public, industrial, or military facilities, it is necessary to be able to predict the behavior of shock waves in any environment. However, while the physical phenomena that occur in free field are well known, they cannot be applied to follow the path of a shock wave in a closed medium, where the phenomena are more complex. The aim of the present study was to define the origins of the different reflections and the path followed by the shock waves after the first reflection in a closed environment composed of two chambers separated by a wall with a variable opening. To achieve this, a fast code was developed based on the shortest path algorithm to determine the parameters of the shock wave at any point of a simple geometry. The code was designed from small-scale experiments that enabled the predictive laws of the distribution of maximum overpressure, total impulse, and the arrival times of the first four peaks to be established. An application of the code is presented in the last part of the paper.
{"title":"Shock wave propagation in a double room model","authors":"G. Ruscade, I. Sochet, K. Djafer","doi":"10.1177/20414196221137918","DOIUrl":"https://doi.org/10.1177/20414196221137918","url":null,"abstract":"Nowadays, the safety of infrastructure and people is a primary concern. To ensure safety in public, industrial, or military facilities, it is necessary to be able to predict the behavior of shock waves in any environment. However, while the physical phenomena that occur in free field are well known, they cannot be applied to follow the path of a shock wave in a closed medium, where the phenomena are more complex. The aim of the present study was to define the origins of the different reflections and the path followed by the shock waves after the first reflection in a closed environment composed of two chambers separated by a wall with a variable opening. To achieve this, a fast code was developed based on the shortest path algorithm to determine the parameters of the shock wave at any point of a simple geometry. The code was designed from small-scale experiments that enabled the predictive laws of the distribution of maximum overpressure, total impulse, and the arrival times of the first four peaks to be established. An application of the code is presented in the last part of the paper.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42989899","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}
Pub Date : 2022-10-26DOI: 10.1177/20414196221136159
Shuoyan Zhang, Chuan-bo Zhou
Subway station is usually located in the dense area of urban buildings (structures). The blasting construction of subway station foundation pit is bound to have adverse effects on adjacent buildings (structures). Therefore, it is necessary to study the dynamic response of the building (structure) and propose the safety threshold of vibration velocity. Based on the foundation pit blasting project of Hejialong Station of Wuhan Rail Transit Line 12, the vibration monitoring of the field blasting test is carried out. Combined with LS-DYNA numerical simulation software, the dynamic response characteristics of a reinforced concrete rigid frame natatorium near the foundation pit are studied, and safety thresholds for structural vibration velocities are derived. It is worth noting that the structure is a large span reinforced concrete rigid frame structure, which is different from the general reinforced concrete frame structure. The safe allowable vibration velocity in the specification is not fully applicable to the structure. Therefore, it is necessary to focus on the dynamic response of the structure under the blasting effect and propose the safety threshold of structural vibration velocity, which can provide reference for the subsequent foundation blasting. The results are as follows: Blasting seismic waves in different propagation media, their energy attenuation is different. By analyzing the vibration velocity of reinforced concrete rigid frame structures, it is found that the high-level amplification effect occurred at specific height range. In addition, the vibration velocity changes abruptly at the parts where the shape and dimensions of the rigid frame cross-section change. The peak vibration velocity and the maximum principal stress of the concrete elements were statistically analyzed to obtain the linear relationship equation, and the vibration velocity safety control threshold of the structure was predicted to be V = 5.089 cm/s.
{"title":"Study on dynamic response and safety control of reinforced concrete rigid frame structure under foundation pit blasting","authors":"Shuoyan Zhang, Chuan-bo Zhou","doi":"10.1177/20414196221136159","DOIUrl":"https://doi.org/10.1177/20414196221136159","url":null,"abstract":"Subway station is usually located in the dense area of urban buildings (structures). The blasting construction of subway station foundation pit is bound to have adverse effects on adjacent buildings (structures). Therefore, it is necessary to study the dynamic response of the building (structure) and propose the safety threshold of vibration velocity. Based on the foundation pit blasting project of Hejialong Station of Wuhan Rail Transit Line 12, the vibration monitoring of the field blasting test is carried out. Combined with LS-DYNA numerical simulation software, the dynamic response characteristics of a reinforced concrete rigid frame natatorium near the foundation pit are studied, and safety thresholds for structural vibration velocities are derived. It is worth noting that the structure is a large span reinforced concrete rigid frame structure, which is different from the general reinforced concrete frame structure. The safe allowable vibration velocity in the specification is not fully applicable to the structure. Therefore, it is necessary to focus on the dynamic response of the structure under the blasting effect and propose the safety threshold of structural vibration velocity, which can provide reference for the subsequent foundation blasting. The results are as follows: Blasting seismic waves in different propagation media, their energy attenuation is different. By analyzing the vibration velocity of reinforced concrete rigid frame structures, it is found that the high-level amplification effect occurred at specific height range. In addition, the vibration velocity changes abruptly at the parts where the shape and dimensions of the rigid frame cross-section change. The peak vibration velocity and the maximum principal stress of the concrete elements were statistically analyzed to obtain the linear relationship equation, and the vibration velocity safety control threshold of the structure was predicted to be V = 5.089 cm/s.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49504535","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}
Pub Date : 2022-09-30DOI: 10.1177/20414196221116650
Huazhang Cao, N. Jiang, Yingkang Yao, Jinshan Sun, Yiwen Huang
Urban concrete pipelines are prone to damage in blasting projects such as excavation of adjacent metro tunnels. Therefore, it is necessary to evaluate the safety of buried concrete pipeline subjected to blasting vibration. Based on the field blasting test of full-scale buried concrete pipeline, considering the factor of pipeline diameter, the dynamic response of concrete pipelines with different diameters was studied by using finite element software ANSYS/LS-DYNA. According to dimensional analysis, a prediction model of particle peak velocity (PPV) considering pipeline diameter was established. Combined with the tensile strength of concrete, the safety criterions of PPV for concrete pipeline with different diameters were proposed, which provided guidance for actual blasting.
{"title":"Safety assessment of concrete pipeline considering the effect of pipe diameter subjected to blasting vibration","authors":"Huazhang Cao, N. Jiang, Yingkang Yao, Jinshan Sun, Yiwen Huang","doi":"10.1177/20414196221116650","DOIUrl":"https://doi.org/10.1177/20414196221116650","url":null,"abstract":"Urban concrete pipelines are prone to damage in blasting projects such as excavation of adjacent metro tunnels. Therefore, it is necessary to evaluate the safety of buried concrete pipeline subjected to blasting vibration. Based on the field blasting test of full-scale buried concrete pipeline, considering the factor of pipeline diameter, the dynamic response of concrete pipelines with different diameters was studied by using finite element software ANSYS/LS-DYNA. According to dimensional analysis, a prediction model of particle peak velocity (PPV) considering pipeline diameter was established. Combined with the tensile strength of concrete, the safety criterions of PPV for concrete pipeline with different diameters were proposed, which provided guidance for actual blasting.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":"14 1","pages":"390 - 406"},"PeriodicalIF":2.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47457743","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}
Pub Date : 2022-09-26DOI: 10.1177/20414196221118595
Obed Samuelraj Isaac, Omar Ghareeb Alshammari, E. Pickering, S. Clarke, S. Rigby
Blast–obstacle interaction is a complex, multi-faceted problem. Whilst engineering-level tools exist for predicting blast parameters (e.g. peak pressure, impulse and loading duration) in geometrically simple settings, a blast wave is fundamentally altered upon interaction with an object in its path, and hence, the loading parameters are themselves affected. This article presents a comprehensive review of key research in this area. The review is formed of five main parts, each describing: the direct loading of a blast wave on the surface of a finite-sized structure; the modified pressure of the blast wave in the wake region of three main obstacle types – blast walls, obstacles, wall/obstacle hybrids; and finally, a brief description of some methods for predicting loading parameters in such blast–obstacle interaction settings. Key findings relate to the mechanisms governing blast attenuation, for example, diffraction, reflection (diverting away from the target structure), expansion/volume increase, vortex creation/growth, as well as obstacle properties influencing these, such as porosity (blockage ratio), obstacle shape, number of obstacles/rows, arrangement and surface roughness.
{"title":"Blast wave interaction with structures – An overview","authors":"Obed Samuelraj Isaac, Omar Ghareeb Alshammari, E. Pickering, S. Clarke, S. Rigby","doi":"10.1177/20414196221118595","DOIUrl":"https://doi.org/10.1177/20414196221118595","url":null,"abstract":"Blast–obstacle interaction is a complex, multi-faceted problem. Whilst engineering-level tools exist for predicting blast parameters (e.g. peak pressure, impulse and loading duration) in geometrically simple settings, a blast wave is fundamentally altered upon interaction with an object in its path, and hence, the loading parameters are themselves affected. This article presents a comprehensive review of key research in this area. The review is formed of five main parts, each describing: the direct loading of a blast wave on the surface of a finite-sized structure; the modified pressure of the blast wave in the wake region of three main obstacle types – blast walls, obstacles, wall/obstacle hybrids; and finally, a brief description of some methods for predicting loading parameters in such blast–obstacle interaction settings. Key findings relate to the mechanisms governing blast attenuation, for example, diffraction, reflection (diverting away from the target structure), expansion/volume increase, vortex creation/growth, as well as obstacle properties influencing these, such as porosity (blockage ratio), obstacle shape, number of obstacles/rows, arrangement and surface roughness.","PeriodicalId":46272,"journal":{"name":"International Journal of Protective Structures","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45712670","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}
Pub Date : 2022-09-25DOI: 10.1177/20414196221120511
P. R. Nowak, T. Gajewski, P. Peksa, P. Sielicki
The clearance of underwater ordnance is one of the most complex tasks entrusted to appropriately trained and equipped soldiers. State-of-the-art knowledge in this area is rarely published and is most often possessed by a narrow group of navy specialists. The aim of this paper was to find a link between the existing mathematical models for the peak pressure of underwater explosion with measurements of small charge detonations for long ranges to the observation point in real life scenarios. We have shown the results of the research in which the underwater explosion tests were presented for different TNT equivalents and standoff distances and thus distance ratios. The curves of pressure versus time of ignition were reported. The measurements were confronted with empirical formulas. The comparison showed large, but expected, differences, since the empirical formulas are advised for smaller distance ratios. Based on the conclusions from the study, the new methodology to identify the loading from underwater explosions based on a database collected was postulated. By creating a survey methodology for ships crew for recording explosion parameters, a large number of events can be registered without a strict setup of the test area. The database obtained can be used by military commanders to identify the explosive hazard in the Baltic Sea region.
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