International Journal of Impact Engineering最新文献

{"title":"Crushing responses and energy absorption characteristics of the dynamic stiffening porous material subjected to different strain rates","authors":"","doi":"10.1016/j.ijimpeng.2024.105117","DOIUrl":"10.1016/j.ijimpeng.2024.105117","url":null,"abstract":"<div><p>Porous material (PM) has excellent energy absorption performance and is widely used as an impact-energy absorber. However, the PM may provide little utility when the impact conditions change. Shear stiffening gel (SSG) with an extremely strong viscosity effect can be as a dynamic responding fortifier to overcome the limitation of PMs. In this paper, a rate-dependent, smart energy-absorbing material (SSG/PM) is fabricated by incorporating SSG that is reinforced with CaCO₃ particles onto the PM. Aided by the dynamic compression experiments at the strain rate range of 0.001 to 100 s⁻¹, both SSG/PM and neat PM are assessed and compared for crushing performance. Results reveal that the SSG/PM exhibits a pronounced dynamic stiffening characteristic in response to various strain rates owing to the rate-dependent phase transition of embedded SSG, thereby contributing to enhancing the PM skeleton's ability to withstand deformation. The SSG/PM displays a noteworthy boost in energy absorption (up to 831.98 %). Moreover, the influence of loading rate, particle mass fraction, and PM aperture size are also examined. The findings indicate that its crushing resistance and energy absorption capability are enhanced with the increase in strain rate, demonstrating the ability to adapt to various dynamic scenarios. The use of a higher particle mass fraction and smaller aperture size helps to improve the energy absorption capability of the SSG/PM. Additionally, quantitative energy analysis is implemented in which the energy dissipation mechanisms of the SSG/PM are attributed to the synergistic interaction of skeleton deformation, shear stiffening effects, and particle enhancement. It is ascertained that as the loading rate increases, the shear stiffening effect continues to strengthen; the particle content effect exhibits a rising-falling trend; while the skeleton deformation shows a rate-independent feature. This study sheds light on the crushing behaviors and corresponding energy dissipation mechanisms of SSG-based composites, thereby providing valuable insights for the design of SSG-based composites.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24002422/pdfft?md5=ab4893bb9f666d2edcbb282e11f76cc4&pid=1-s2.0-S0734743X24002422-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of freeze recovery method on high-speed fracture in metal cylindrical shells","authors":"","doi":"10.1016/j.ijimpeng.2024.105109","DOIUrl":"10.1016/j.ijimpeng.2024.105109","url":null,"abstract":"<div><p>The freeze recovery method (FRM) is a crucial approach for investigating the high-speed fracture process of metal cylindrical shells under explosive loading. However, the precise impacts of the recovery process on the deformation and fracture behavior of such shells remain unclear, significantly constraining the widespread application of this method in high-speed fracture studies. This paper quantitatively evaluates the effects of the expansion contour, fracture mode, and damage state of intermediate shells at different stages of fracture development using a crack evolution simulation method and nondestructive crack detection technique. The recovered shell contour can effectively represent the free expansion contour of the shell at the equivalent moment, with an error of less than 4%. Impact induces tensile cracks on the outer wall of the shell, which leads to changes in the local fracture mode. A method of crack elimination and equivalence in the damage statistics of the recovered shell is proposed to address this effect. The recovered shell can characterize the damage evolution during free expansion at the equivalent moment after eliminating the influence of excess tensile cracks. Based on the principle of stress analysis and energy conservation, the formation mechanism of tensile cracks in the outer wall of the shell is explored, and the correlation between tensile cracks and recovery time is elucidated. The study shows that the impact of fracture damage caused by freezing recovery is gradually reduced over time. The improved freezing recovery method based on the hard recovery principle is successfully used to recover the multistage intermediate shell, meeting the demand for obtaining the transient physical model in the high-speed fracture field.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24002343/pdfft?md5=c270b69a694b0f3e35ae921acf1ba588&pid=1-s2.0-S0734743X24002343-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Blast impact on the density-based tri-layered polyurethane foam","authors":"","doi":"10.1016/j.ijimpeng.2024.105108","DOIUrl":"10.1016/j.ijimpeng.2024.105108","url":null,"abstract":"<div><p>Cellular solids are interesting materials for blast energy absorption because of their high porosity, cell structure, and unique mechanical properties. Also, it will undergo graded compression over the same foam density. Hence, in this study, an experimental investigation of blast pressure impact on the trilayered sequences made of three different polyurethane (PU) foam densities of equal thickness, such as D1-29.201 kg/m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>, D2-59.692 kg/m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>, and D3-107.720 kg/m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span> is carried out. The force transmitted <span><math><mrow><mo>(</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>)</mo></mrow></math></span> on the reaction plate and incident force on the blast impact face are recorded. The maximum force amplification <span><math><mrow><mo>(</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>a</mi><mi>m</mi><mi>p</mi></mrow></msub><mo>)</mo></mrow></math></span> of the 63.79% was observed in the S5 and the minimum of 6.19% in S4. Thus the reduction in <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>a</mi><mi>m</mi><mi>p</mi></mrow></msub></math></span> in S4 compared to S5 is 90.3%. Similarly, the energy absorbed <span><math><mrow><mo>(</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>a</mi><mi>b</mi><mi>s</mi></mrow></msub><mo>)</mo></mrow></math></span> by the trilayer is a maximum of 24.80 J in S2 and a minimum of 3.60 J in S3. The <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>a</mi><mi>b</mi><mi>s</mi></mrow></msub></math></span> increased to 85.48% in S2 solely by altering the layer sequences in S3. Hence, the location of the density in the layer sequences plays a key role in effective blast mitigation on different response measures.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24002331/pdfft?md5=f7c26cbc6f47a0b49f954fe8cb10d7ff&pid=1-s2.0-S0734743X24002331-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The achievement of constant strain rates in electromagnetic Hopkinson bar test","authors":"","doi":"10.1016/j.ijimpeng.2024.105121","DOIUrl":"10.1016/j.ijimpeng.2024.105121","url":null,"abstract":"<div><div>During the electromagnetic Hopkinson bar test, a sinusoidal shape of the stress wave could be generated and applied to the specimen. It is difficult to achieve a constant strain rate during the tests for the metal materials. This paper introduces a novel technique that can generate a bilinear shape of the stress wave based on the Fourier transform in which the multiple sinusoidal waves are superimposed. The mechanism of stress wave generation is analyzed theoretically and simulated numerically. On this basis, a new set of electromagnetic Hopkinson bar experimental equipment is set- up. The dynamic compression test of the material is carried out by the experimental device. The experimental results demonstrate that the specimens have a constant strain rate when subjected to bilinear stress wave impact. The regulation of stress wave shape can also be controlled by adjusting the electromagnetic emission parameters. Hence, the application scope of the ESHB technique in investigating dynamic properties can be expanded to various types of materials.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peridynamics modelling of projectile penetration into concrete targets","authors":"","doi":"10.1016/j.ijimpeng.2024.105110","DOIUrl":"10.1016/j.ijimpeng.2024.105110","url":null,"abstract":"<div><p>A non-ordinary state-based peridynamics (NOSB-PD) model is proposed to simulate the projectile penetration into concrete targets. In this model, the Kong-Fang concrete material model recently proposed is firstly implemented into the NOSB-PD framework to describe the complex dynamic behavior and failures in concrete material subjected to penetration loading, and then an improved point-to-volume discrete frictional contact model is proposed to simulate the physical interaction between projectile and target. After the mesh-free discretization and explicit time integration, the proposed NOSB-PD model is used to numerically predict two sets of projectile penetration experiments into low-strength and high-strength concrete targets. And numerical predictions are found to be in good agreements with corresponding test data including penetration depth, projectile deceleration, deformation of projectile and failures in concrete targets.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24002355/pdfft?md5=e1ca2bc0688a125002715bc3e786bd23&pid=1-s2.0-S0734743X24002355-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical behaviors of metakaolin-based foamed geopolymer (MKFG) under dynamics loading","authors":"","doi":"10.1016/j.ijimpeng.2024.105106","DOIUrl":"10.1016/j.ijimpeng.2024.105106","url":null,"abstract":"<div><p>In this study, metakaolin-based foam geopolymer (MKFG) with densities of 400 kg/m³, 600 kg/m³, and 800 kg/m³ were prepared. The effect of weak links on the dynamic mechanical behavior, damage morphology, and energy absorption capacity (<em>SEA</em>_p) of the MKFG was studied by X-CT analysis, Split Hopkinson Pressure Bar (SHPB) test, and fractal analysis. The results show that the connected porosity of MKFG rises with decreasing density. The sensitivity of the damage level to strain rate decreases with elevated connected porosity, which is because the stress concentrations caused by weak links. The amplifying effect of strain rate on the dynamic compressive strength of MKFG diminishes as the connected porosity increases. The sensitivity of <em>SEA</em>_p to the damage level rises with a decrease in the connected porosity. Finally, the simulation results corroborate that the distribution of connected pores has a significant influence on the damage process of the MKFG.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24002318/pdfft?md5=5ff77ac137d8a4e5cc83805243bdf96e&pid=1-s2.0-S0734743X24002318-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142169178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of dynamic response of full-scale RC beams under high-energy impact","authors":"","doi":"10.1016/j.ijimpeng.2024.105104","DOIUrl":"10.1016/j.ijimpeng.2024.105104","url":null,"abstract":"<div><p>Most impact tests of reinforced concrete (RC) structures are small-energy and reduced-scale tests. Due to the size effects under strain rate, there are large differences in the dynamic responses between reduced-scale and full-scale tests, which makes it inappropriate to design full-scale structures under impact loading based on reduced-scale test results. This paper presents the first results to compare the effects of drop weight impact tests on reduced and full-scale reinforced concrete (RC) beams. The experimental results are used to identify limits of applicability of the similarity laws that have been developed based on low-energy impact tests on reduced-scale structures. Due to low stiffness of the reduced-scale specimens, their failure mode is typical of bending. In contrast, the full-scale specimens have much higher bending stiffness and therefore are more prone to shear failure. Since the ratio of impact force to reaction force decreases as the geometric dimensions of RC beams increase, it is likely that the reaction forces of full-scale RC beams inferred from theories based on the reduced-scale impact test will be lower than in real situation, which could lead to unsafe design. The existing effective length analysis method only considers the stage before the impact force reaches the peak value and cannot deal with the change in effective length of full-scale RC beams with nonlinear deformation. The current theory of energy for impact test that considers the total mass of the structure cannot accurately reflect the effect of full-scale tests in which the loss of energy of the structure is much higher than the absorbed energy. The energy analysis method for full-scale structures is more reasonable when considering the effective mass. The guidance of reduced-scale test is not applicable in full-scale test, and the large deviation of forces between the reduced-scale and full-scale structures by using the DLV systems. To rectify these problems, this paper proposes a similarity law for GVH systems.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X2400229X/pdfft?md5=f445a8492ac1eaaf4e5039a47eadd414&pid=1-s2.0-S0734743X2400229X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142233907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A modified bond-based peridynamic approach for rigid projectile perforation on concrete slabs","authors":"","doi":"10.1016/j.ijimpeng.2024.105102","DOIUrl":"10.1016/j.ijimpeng.2024.105102","url":null,"abstract":"<div><p>Peridynamic (PD) has a unique advantage in describing the crack growth and fragmentation of brittle materials. Concerning the dynamic behaviors and failure patterns of concrete slabs under projectile perforations, a modified bond-based PD approach maintaining both the easy implementation and computational stability characteristics was firstly developed from the following three aspects, (i) a rate-dependent PD constitutive model was proposed for describing the dynamic behaviors of concrete; (ii) a progressive damage criterion considering the tension-compression anisotropy, softening behavior, and strain rate effect of concrete was incorporated to more accurately reproduce the damage and failure of concrete; (iii) an improved micro-modulus function related to bond length was introduced to reveal the internal length effect of bond force. Then, numerical simulations of projectile perforation on concrete slabs by utilizing the developed modified bond-based PD approach, as well as the corresponding sensitivity analyses of discretization parameters including horizon size and particle spacing were performed. Based on the recommended horizon size and particle spacing, the predicted residual velocity of projectile and failure patterns of concrete slabs exhibited an excellent agreement with the test data. Furthermore, by comparisons of the traditional bond-based PD and classical finite element methods, the superiority of developed approach in describing the perforation damage of concrete targets against projectile impact was demonstrated. Finally, the modified bond-based PD approach was employed to blind simulate the projectile normal and oblique perforating multi-layered spaced concrete target plates. It was found that the modified PD model reasonably predicted the terminal ballistic trajectory, deflection angle, and residual velocity of projectile, as well as the failure patterns of target plates. The present work provides a new way to predict the terminal ballistic effect of projectile and dynamic behaviors of concrete slabs.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24002276/pdfft?md5=cf3f80845e0cf29b0eb9bffa88eb6679&pid=1-s2.0-S0734743X24002276-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142163486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From quasi-static to dynamic: Experimental study of mechanical and fracture behaviour of epoxy resin","authors":"","doi":"10.1016/j.ijimpeng.2024.105101","DOIUrl":"10.1016/j.ijimpeng.2024.105101","url":null,"abstract":"<div><p>Epoxy polymers are extensively used in various engineering applications such as aerospace, defence, sports, automotive etc. This article focuses on the in-depth mechanical characterisation of EPOFINE®-1564, a Bisphenol-A-based liquid epoxy resin under various loading conditions. To predict the tensile and compressive behaviour of the representative epoxy resin, quasi-static experiments were performed in the range of 10⁻⁴ to 10⁻² <em>s</em>⁻¹ on Universal testing machine (UTM) while the dynamic experiments were conducted using Split Hopkinson Pressure Bar (SHPB) for high strain rates (1136–2833 <em>s</em>⁻¹). In this study, 3D Digital Image Correlation (DIC) was also used to evaluate the specimen's full-field displacement profile over a wide range of strain rates. Analysis of various mechanical properties such as elastic modulus, yield strength, and ultimate strength, revealed that the epoxy polymer is strain rate dependent within the considered strain rate range. For understanding the fracture behaviour, three-point bend (TPB) experiments were also carried out for both quasi-static (1–10 mm/min) as well as dynamic (10–15 m s^-1) regimes. Dynamic fracture experiments were performed using the modified Hopkinson Pressure Bar (MHPB). The fracture toughness was determined through load vs crack mouth opening displacement (CMOD). Fracture toughness was found to increase with the displacement rate due to the significant plastic deformation under quasi-static range. Conversely, it was found to decrease under dynamic loading because of absence of plastic deformation resulting in brittle fracture. The fracture surface of the specimen was examined through a high magnification digital microscope.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24002264/pdfft?md5=497b7852a5129a42db245f9167a90aea&pid=1-s2.0-S0734743X24002264-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142169179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The energy absorption characteristics and structural optimization of titanium/UHMWPE fiber metal laminates under high-speed impact","authors":"","doi":"10.1016/j.ijimpeng.2024.105097","DOIUrl":"10.1016/j.ijimpeng.2024.105097","url":null,"abstract":"<div><p>Fiber-metal laminates (FMLs), known for their lightweight and high strength, are widely used in structural protection in the fields of shipbuilding, military, and aerospace. Experiments were conducted using 12.7 mm hard spherical projectiles at speeds ranging from 915.7 – 1290 6 m per second to study the high-speed impact on FMLs composed of titanium and Ultra-high Molecular Weight Polyethylene(UHMWPE). The primary failure modes of the fibers were tensile failure and compressive shear failure. With increasing impact velocity, the proportion of tensile failures in the fibers gradually decreased, transitioning to shear plug failure as the main failure mode, while the titanium alloy primarily experienced erosive perforation and petal-shaped tearing. At a speed of 1290 6 m/s, the titanium alloy began to exhibit significant adiabatic shear tearing in four directions. Further, a three-dimensional numerical model was established, which, through theoretical analysis and experimental validation, proved to be highly reliable. Using this theoretical model, a deeper analysis of the dynamic response and penetration mechanism of the structure was conducted, explaining the energy distribution mechanism and dynamic response mechanisms of various parts. Based on this model, improvements and optimizations were made to the laminar structure of the UHMWPE/titanium alloy FML. Placing metal at the back maximized energy absorption but led to more pronounced bulging.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24002227/pdfft?md5=dcee9f488fa3b019937a182f6cb25486&pid=1-s2.0-S0734743X24002227-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142163575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}