{"title":"Stress wave effects and their mechanisms on stress-strain curves in the elastic phase of SHPB tests","authors":"","doi":"10.1016/j.ijimpeng.2024.105061","DOIUrl":"10.1016/j.ijimpeng.2024.105061","url":null,"abstract":"<div><p>In Split Hopkinson Pressure Bar (SHPB) tests, the stress wave effects during the elastic phase of the stress-strain curve and their influence mechanisms are crucial. Due to the extremely short duration of the elastic deformation phase, the stress wave effects on the specimen during this stage cannot be ignored. This leads to significant errors in the obtained elastic stress-strain curves. However, the dynamic compressive elastic stress-strain relationship forms the basis for studying the viscoelastic behavior of materials. Accurate determination of elastic yield stress and yield strain is also essential for deriving accurate plastic stress-strain relationships. Quantitative research on the stress wave effects during the elastic compression phase of SHPB tests is fundamental for decoupling and obtaining accurate material elastic curves. This paper conducts a quantitative theoretical analysis of the structural effects caused by stress wave evolution during the elastic compression phase, based on the assumption of plane waves. It studies the deviation characteristics and main factors of the phenomenological engineering stress-strain curves of the specimen compared to the actual material stress-strain curves under different conditions, revealing the influence rules and mechanisms of this deviation. The maximum stress deviation value and its corresponding dimensionless time, as well as the variation trend of the maximum stress deviation value within different fluctuation intervals, are calculated. Additionally, the study investigates the cases where the incident wave is arc-shaped or a combination of arc and linear waves. The findings provide theoretical references for the precise design and accurate data processing of SHPB tests.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943775","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":"A three-dimensional coupled thermo-elastic-plastic phase field model for the brittle-ductile failure mode transition of metals","authors":"","doi":"10.1016/j.ijimpeng.2024.105062","DOIUrl":"10.1016/j.ijimpeng.2024.105062","url":null,"abstract":"<div><p>Dynamic brittle fracture and shear banding are two typical failure modes of metals, and the transformation of the brittle-ductile failure mode has been observed in the Kalthoff test. This paper establishes a thermo-elastic-plastic coupled three-dimensional phase field model to simulate brittle-ductile failure mode transition of metals. The expression for the variation of the Taylor-Quinney coefficient with stress triaxiality is adopted, and the critical energy release rate is automatically adjusted using the Taylor-Quinney coefficient. Then, the Kalthoff test is simulated using the proposed model. The brittle-ductile failure mode transformation phenomenon is reproduced, which agrees well with the experimental results. It can be well proved that impact velocity is crucial in determining the transition to failure mode. At low-velocity impact, the energy is insufficient to drive the plastic accumulation of the shear band, resulting in brittle tensile fracture. At high-velocity impact, the energy is sufficient to drive the formation of adiabatic shear bands, resulting in tensile shear failure. In addition, three-dimensional simulations show that the tip of the shear band exhibits a crescent-shaped non-two-dimensional extension state under finite thickness. This numerical framework provides a predictive tool to understand the evolution of the dynamic failure of metals under impact loading.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141841315","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":"Exploring the enhanced energy-absorption performance of hybrid polyurethane(PU)-foam-filled lattice metamaterials","authors":"","doi":"10.1016/j.ijimpeng.2024.105058","DOIUrl":"10.1016/j.ijimpeng.2024.105058","url":null,"abstract":"<div><p>In this study, the experimental and numerical investigations are performed to explore the enhanced energy-absorption performance of hybrid polyurethane(PU)-foam-filled lattice metamaterials subjected to low-velocity impact (LVI). Initially, three types of lattices are prepared by additive manufacturing technique, and then filled with the PU foams using freeze casting technique. Experimental and numerical LVI tests have been performed to characterize the energy-absorption performance of pure and hybrid lattice structures. These experimental and numerical results indicate that the hybrid structures possess the longer elastoplastic and damage evolution stages than the pure ones. The overall absorbed energy of the hybrid structures is distinctly higher than the sum of pure lattices and PU foams, disclosing the enhancement of the energy-absorption capacity induced by the PU-foam-filling. Besides, the pure and hybrid hyperbolic lattice structures exhibit the better energy-absorption capacity than two other types, due to the compression-twist effect. As the foam collapse occurs, the lattice damages are significantly inhibited in the hybrid ones. It reveals that the filled foams protect the embedded lattices via causing foam collapse to dissipate impact energy. Meanwhile, foam-filling prevents the excessive twisting behavior of the hyperbolic lattice and makes the stress distribute more evenly.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141848855","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":"Research on the penetration performance of shaped charge jet into block stone concrete targets","authors":"","doi":"10.1016/j.ijimpeng.2024.105060","DOIUrl":"10.1016/j.ijimpeng.2024.105060","url":null,"abstract":"<div><p>Experiment and numerical simulation were conducted to investigate the penetration performance of shaped charge jet into block stone concrete targets. The experiment has shown that the jet undergoes deflection and other phenomena during its penetration of block stone concrete. Improvements have been made to the methods used by previous scholars for constructing aggregate particles, resulting in a particle model that more closely resembles the true shape of the aggregate. A novel method for judging the intersection of aggregate particles based on the Plucker coordinate system was proposed. In comparison with traditional methods, this method is not constrained by the shape of aggregate particles. By utilizing dynamic simulation software to replicate aggregate settlement during the production process of concrete targets, a 3D meso-scale model of concrete was successfully established. Numerical simulations were conducted according to the experimental settings, with the results demonstrating good consistency between the experimental and numerical simulations, thus confirming the reliability of the model and methodology presented in this article. Additionally, the numerical simulation results suggest that the aggregate content significantly influences the degree of interference, penetration depth, and damage zone range of the jet, while the impact position primarily affects the deflection of the jet. This article provides a numerical simulation method for future research on the penetration and damage mechanism of shaped charge jet considering the 3D meso-scale model of concrete.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141849668","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":"Quasi - static and impact performance study of a three-dimensional negative Poisson's ratio structure with adjustable mechanical properties","authors":"","doi":"10.1016/j.ijimpeng.2024.105057","DOIUrl":"10.1016/j.ijimpeng.2024.105057","url":null,"abstract":"<div><p>The mechanical properties of most materials with a negative Poisson's ratio (NPR) cannot be flexibly adjusted after being designed to meet complex engineering requirements. To ensure the changes of those materials’ relative density are minimal when overcoming these limitations, this study proposes a novel method that adjusts the mechanical performance by grooving the structure and adjusting the angle of the diagonal support rod. Unlike traditional methods that involve adding 'ribs' to the structure for adjustability, this approach focuses on the design of the structure itself. To analyze the large deformation behavior of unit-cell lattices, we established a theoretical model based on plastic deformation theory and derive the relationship between the number of unit-cell lattices and the relative density of multi-cell lattices. Experimental samples were fabricated by using selective laser melting (SLM). Meanwhile, the accuracy of the finite element results was verified by quasi-static compression experiments and impact experiments. Then the validated finite element model is then utilized to discuss the influence of structural parameters on mechanical properties. In addition, we also studied the influence of medium and low-speed impact loads on the deformation characteristics, mechanical properties, and energy absorption (EA) of the structures. The results demonstrate the reliability of the design method, showcasing its potential to achieve on-demand adjustability of stress, stiffness, and strength to meet complex engineering requirements. Notably, the adjustment range of peak load is from 24.55 MPa at the lower limit <em>α</em> = 60° to 48.29 MPa at the upper limit <em>α</em> = 90°, with an adjustment range of 23.74 MPa. The adjustment range of the average platform stress is from 10.8 MPa at the lower limit of <em>α</em> = 60° to 24.34 MPa at the upper limit of <em>α</em> = 80°, and the adjustment range reaches 13.54 MPa. This study provides new insights on intelligent protection engineering and the adjustable mechanical properties of metamaterials.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141851792","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":"Blast-resistance characteristics and design of steel wire reinforced ultra-high performance concrete slabs","authors":"","doi":"10.1016/j.ijimpeng.2024.105059","DOIUrl":"10.1016/j.ijimpeng.2024.105059","url":null,"abstract":"<div><p>Steel wire reinforced ultra-high performance concrete (SWRUHPC) offers exceptional resistance to impacts and blast, making it a promising construction material for infrastructure with blast-resistance demands. However, limited research has been conducted on the blast-resistance characteristics and design of SWRUHPC elements under blast loading, particularly in considering multiple influencing parameters and levels. Therefore, this study employed finite element simulation methods to investigate the influence of scaled distance (<em>Z</em>), reinforcement ratio (<em>ρ</em>) and slab thickness (<em>D</em>) as well as slab length (<em>L</em>) on the failure mode and maximum deflection of SWRUHPC slabs. Range analysis and variance analysis methods were used to quantitively analyze the effects of various factors on the blast resistance performance, culminating in the proposal of a design formula for SWRUHPC slabs. The results demonstrated that SWRUHPC exhibits superior blast resistance compared to ordinary concrete, effectively reducing the occurrence of concrete spalling and splashing, thus enhancing overall structural resilience in blast scenarios. Among the four factors analyzed, their influence on maximum deflection follows this order: <em>D</em> > <em>Z</em> > <em>ρ</em> > <em>L</em>. Notably, the maximum deflection decreases by 82 % when the slab thickness increases from 40 mm to 90 mm. Additionally, the established design formula for SWRUHPC slabs under different scaled distances shows good agreement with the numerical simulation results, offering valuable design guidelines for SWRUHPC slabs in protective engineering structures.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141841961","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":"Dynamic crushing failure and energy absorption of natural bamboo-culms under axial low-velocity impact","authors":"","doi":"10.1016/j.ijimpeng.2024.105056","DOIUrl":"10.1016/j.ijimpeng.2024.105056","url":null,"abstract":"<div><p>The axial crushing behavior of natural bamboo culms with various growth ages under quasi-static and low-velocity impact was experimentally investigated in this study. First, the macro- and micro- structural features of bamboo culms were observed, and the tensile mechanical properties of bamboo materials were measured. And then the typical crushing responses and deformation/failure patterns of dynamically-loaded bamboo culms were presented, compared with those under quasi-static load. Whereafter, the strain field distribution and energy absorption characteristics of bamboo culms were analyzed, and the crashworthiness of tested bamboo culms under impact load was evaluated. Finally, the energy absorption capacity of bamboo culms was compared with typical metallic circular tubes (made of Q235 steel and AA6061-T6 aluminum alloy) and other widely-used engineering materials/structures. The results indicate that the brittle fracture is the dominant failure mode of bamboo culms, which includes the splitting mode for internodal specimens and the bulging mode for nodal specimens. The nodal bamboo culms have a superior energy absorption capacity and crashworthiness compared to internodal bamboo culms, attributed to the dense distribution of vascular bundles and high anti-split strength of bamboo nodes. The energy absorption capacity of 1-year-old nodal bamboo culms is better than that of aluminum or steel tubes, and the corresponding <em>SEA</em> value of nodal bamboo culms has reached 11.8 J/g, while it is 10.65 J/g of the aluminum tube and 6.65 J/g of the steel tube, respectively.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141844391","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":"Experimental and numerical investigation on projectile penetration resistance of prefabricated concrete targets","authors":"","doi":"10.1016/j.ijimpeng.2024.105053","DOIUrl":"10.1016/j.ijimpeng.2024.105053","url":null,"abstract":"<div><p>Prefabricated ultra-high-performance concrete (UHPC) target has the advantages of prominent anti-penetration capability and good construction quality. However, the interfaces in the prefabricated target would inevitably reduce its penetration resistance. To deal with this problem, a new prefabricated technique with the use of wet joints and rebars is proposed. To demonstrate the effectiveness of the proposed technique, two sets of projectile penetration tests on prefabricated targets assembled by prefabricated UHPC blocks, wet joints and rebars were firstly conducted and compared with corresponding experimental results of monolithic targets, demonstrating the comparable penetration resistance between prefabricated targets and corresponding monolithic targets. Then, based on the Kong–Fang model and SPG method, the numerical models of the two tests were developed and validated against the experimental data. The validated numerical models were further used to investigate the influences of interfaces, wet joints and rebars on the penetration resistance of prefabricated targets. The numerical results found that the horizontal interfaces have a limited influence on the penetration resistance while the vertical interfaces have a strong influence. It also numerically demonstrated the effectiveness of the proposed technique using wet joints and rebars to connect prefabricated blocks. The research results can provide an important reference for the use of prefabricated targets in protective engineering.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141729013","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":"A simulation approach for quantifying ballistic impact damage in ultra-high-performance concrete","authors":"","doi":"10.1016/j.ijimpeng.2024.105055","DOIUrl":"10.1016/j.ijimpeng.2024.105055","url":null,"abstract":"<div><p>In this work, we provide a hydrocode simulation model for high-velocity projectile impact against ultra-high-performance concrete targets and establish a methodology to extract damage quantities from the simulation results. In the parameter derivation process, published and own data stemming from material experiments, such as uniaxial, triaxial, and planar plate impact tests, are used as a starting point. To fill the systematic gaps of strength data for pressures of 1 GPa to 5 GPa and for fractured concretes, residual velocities of projectiles and qualitative target damage information from ballistic experiments with high-hard steel spheres are additionally used as a reference in parametric simulations. All criteria from the comparatively broad data basis are successfully reproduced by the simulation model simultaneously. The simulated damage quantities derived by the proposed extraction procedure are reasonable counterparts to the corresponding experimental measures from earlier published works, allowing a new quality of comparison between both worlds.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0734743X24001799/pdfft?md5=d01e618f0db1a40c02ef933cef938da2&pid=1-s2.0-S0734743X24001799-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141711705","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":"Strain waves on additively manufactured plates for an on-orbit impact detector concept","authors":"","doi":"10.1016/j.ijimpeng.2024.105054","DOIUrl":"10.1016/j.ijimpeng.2024.105054","url":null,"abstract":"<div><p>Orbital debris impacts on spacecraft are an emerging threat to space missions due to the exponential increase in the number of satellites orbiting the Earth. Debris characteristics (size, material, velocity, etc.) are not well known for the size range of 10 mm or less that is undetectable using Earth telescopes or radar observation. The objective of this research was to determine wether a concept designed to detect impact of particles in the ∼1 to 5 mm range, find the location of the impact, and characterize the impacting projectile (velocity, size, angle, density), is feasible.</p><p>The paper describes the design, fabrication, and tests performed on “witness plates” (the concept) made of two parallel layers of additively manufactured aluminum and instrumented with sixteen gages, eight on each layer. Laboratory experiments have shown that the waves can be recorded and properly interpreted to find location of impact, sound speed in the plate, and to estimate impact velocity. It was shown analytically that the amplitude of the first strain wave that propagates from the impact point is expected to decay as 1/<em>r</em>. This was observed as well in the signals recorded in the experiments. CTH computations were performed during the pre-test design phase and the post-test analysis phase. In fact, the numerical simulations have been key and pervasive in this research effort as they provided invaluable insight for the initial design and the correct interpretation of signal anomalies seen during the tests. Additionally, the computations confirmed the <em>1/r</em> law derived analytically, i.e. that the assumptions for the derivation were justified. The main conclusions of the research are that, for a normal impact, the <em>1/r</em> law for front gages can be easily used to determine the diameter of the impactor. It is possible that the back gages could be used to determine the density of the impactor as well. Finally, it was shown that oblique impacts generate an expected assymetry in the signals recorded. Though this aspect should be investigated further, the assymetry is probably uniquely related to the impact angle, which could provide the angle information.</p></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141695593","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}