scholarly journals Mechanically Excellent Nacre-inspired Protective Steel-Concrete Composite against Hypervelocity Impacts

2021 ◽  
Author(s):  
Yong Mei ◽  
Jinming Liu ◽  
Yuan Cui ◽  
Feng Li ◽  
Xuke Tang ◽  
...  
Keyword(s):  
Low Cost ◽  
Impact Resistance ◽  
Target Material ◽  
Structural Similarity ◽  
Structure Design ◽  
Hypervelocity Impact ◽  
Steel Bar ◽  
Brick And Mortar ◽  
Mohs Hardness ◽  
Structural Architecture

Abstract Steel-concrete (SC) composite widely used in military defensive project is due to its impressive mechanical properties, long-lived service, and low cost. However, the growing use of hypervelocity kinetic weapons in the present war puts forward higher requirements for the anti-explosion and penetration performance of military protection engineering. Here, inspired by the special ‘brick-and-mortar’ (BM) structural feature of natural nacre, we firstly construct a nacre-inspired steel-concrete (NISC) engineering composite with 2510 kg/m3, possessing nacre-like lamellar architecture via a bottom-up assembling technique. The NISC engineering composite exhibits nacreous BM structural similarity, high compressive strength of 68.5 MPa, compress modulus of 42.0 GPa, Mohs hardness of 5.5, Young’s modulus of 41.5 GPa, and shear modulus of 18.4 GPa, higher than pure concrete. More interestingly, the hypervelocity impact tests reveal the penetration capability of our NISC target material is obviously stronger than that of pure concrete, enhanced up to about 46.8% at the striking velocity of 1 km/s and approximately 30.9% at the striking velocity of 2 km/s, respectively, by examining the damages of targets, the trajectories, penetration depths, and residual projectiles. This mechanically integrated enhancement can be attributed to nacre-like BM structural architecture derived from assembling the special steel-bar framework-reinforced concrete platelets. This study highlights a key role of nacre-like structure design in promoting the enhanced hypervelocity impact resistance of steel-concrete composites.

scholarly journals Mechanically excellent nacre-inspired protective steel-concrete composite against hypervelocity impacts

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yong Mei ◽  
Jinming Liu ◽  
Yuan Cui ◽  
Feng Li ◽  
Xuke Tang ◽  
...  
Keyword(s):  
Low Cost ◽  
Impact Resistance ◽  
Target Material ◽  
Structural Similarity ◽  
Structure Design ◽  
Hypervelocity Impact ◽  
Steel Bar ◽  
Brick And Mortar ◽  
Mohs Hardness ◽  
Structural Architecture

AbstractSteel–concrete (SC) composite widely used in military defensive project is due to its impressive mechanical properties, long-lived service, and low cost. However, the growing use of hypervelocity kinetic weapons in the present war puts forward higher requirements for the anti-explosion and penetration performance of military protection engineering. Here, inspired by the special ‘brick-and-mortar’ (BM) structural feature of natural nacre, we successfully construct a nacre-inspired steel–concrete (NISC) engineering composite with 2510 kg/m3, possessing nacre-like lamellar architecture via a bottom-up assembling technique. The NISC engineering composite exhibits nacreous BM structural similarity, high compressive strength of 68.5 MPa, compress modulus of 42.0 GPa, Mohs hardness of 5.5, Young’s modulus of 41.5 GPa, and shear modulus of 18.4 GPa, higher than pure concrete. More interestingly, the hypervelocity impact tests reveal the penetration capability of our NISC target material is obviously stronger than that of pure concrete, enhanced up to about 46.8% at the striking velocity of 1 km/s and approximately 30.9% at the striking velocity of 2 km/s, respectively, by examining the damages of targets, the trajectories, penetration depths, and residual projectiles. This mechanically integrated enhancement can be attributed to the nacre-like BM structural architecture derived from assembling the special steel-bar array frame-reinforced concrete platelets. This study highlights a key role of nacre-like structure design in promoting the enhanced hypervelocity impact resistance of steel–concrete composites.

Effect of adhesive interlayers on protective performance of bio-inspired building ceramic covering

2020 ◽  
Vol 23 (16) ◽  
pp. 3446-3455
Author(s):  
Yuyan Sun ◽  
Sheng Wang ◽  
Ziguo Wang
Keyword(s):  
Penetration Depth ◽  
Low Cost ◽  
Impact Resistance ◽  
Epoxy Adhesive ◽  
Building Ceramic ◽  
Ballistic Performance ◽  
Silicone Sealant ◽  
Brick And Mortar ◽  
Maximum Penetration ◽  
The Impact

The brick-and-mortar microstructure of nacre is usually considered as a source of inspiration for the development of strong and tough artificial materials. In this article, a nacre-inspired layered-and-staggered structural building ceramic protective covering was fabricated, and the effect of four types of adhesive materials on the ballistic performance of the protective covering was investigated through the ballistic test. The experimental results showed that under the impact of the 7.62-mm ordinary rifle bullet at a speed of 790–820 m/s, the average crater diameter in the concrete targets with protective covering was reduced by 40%–72%, and the penetration depth in the concrete was reduced by 70%–100%, compared with those of unprotected concrete targets. For the concrete targets with protective covering, that adopting the silicone sealant interlayers exhibited a smaller crater area but a maximum penetration depth, while that adopting the epoxy adhesive interlayers showed a larger crater area but a minimum penetration depth. Since the targets with the low-cost polyurethane sealant interlayers presented the smallest crater area and the shallower penetration depth, it can be concluded that the concrete with the protective covering using polyurethane sealant interlayers showed the better projectile impact resistance.

scholarly journals Towards Sustainable Concrete Composites through Waste Valorisation of Plastic Food Trays as Low-Cost Fibrous Materials

2021 ◽  
Vol 13 (4) ◽  
pp. 2073 ◽  
Author(s):  
Hossein Mohammadhosseini ◽  
Rayed Alyousef ◽  
Mahmood Md. Tahir
Keyword(s):  
Compressive Strength ◽  
Low Cost ◽  
Impact Resistance ◽  
Food Tray ◽  
World Population ◽  
Fibrous Materials ◽  
Palm Oil Fuel Ash ◽  
Waste Plastic ◽  
Compressive Strength Of Concrete ◽  
The Impact

Recycling of waste plastics is an essential phase towards cleaner production and circular economy. Plastics in different forms, which are non-biodegradable polymers, have become an indispensable ingredient of human life. The rapid growth of the world population has led to increased demand for commodity plastics such as food packaging. Therefore, to avert environment pollution with plastic wastes, sufficient management to recycle this waste is vital. In this study, experimental investigations and statistical analysis were conducted to assess the feasibility of polypropylene type of waste plastic food tray (WPFT) as fibrous materials on the mechanical and impact resistance of concrete composites. The WPFT fibres with a length of 20 mm were used at dosages of 0–1% in two groups of concrete with 100% ordinary Portland cement (OPC) and 30% palm oil fuel ash (POFA) as partial cement replacement. The results revealed that WPFT fibres had an adverse effect on the workability and compressive strength of concrete mixes. Despite a slight reduction in compressive strength of concrete mixtures, tensile and flexural strengths significantly enhanced up to 25% with the addition of WPFT fibres. The impact resistance and energy absorption values of concrete specimens reinforced with 1% WPFT fibres were found to be about 7.5 times higher than those of plain concrete mix. The utilisation of waste plastic food trays in the production of concrete makes it low-cost and aids in decreasing waste discarding harms. The development of new construction materials using WPFT is significant to the environment and construction industry.

Lab Testing and Finite Element Method Simulation of Hole Deflector Performance for Radial Jet Drilling

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Bin Wang ◽  
Gensheng Li ◽  
Zhongwei Huang ◽  
Tianqi Ma ◽  
Dongbo Zheng ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Low Cost ◽  
Geometric Model ◽  
Frictional Resistance ◽  
Finite Element Method Simulation ◽  
Optimization Method ◽  
Structure Design ◽  
Coal Bed ◽  
Factors Affecting ◽  
High Pressure Water Jet

Radial jet drilling (RJD) is an efficient approach for improving the productivity of wells in low permeability, marginal and coal-bed methane (CBM) reservoirs at a very low cost. It uses high-pressure water jet to drill lateral holes from a vertical wellbore. The length of the lateral holes is greatly influenced by the frictional resistance in the hole deflector. However, the hole deflector frictional resistance and structure design have not been well studied. This work fills that gap. Frictional resistances were measured in a full-scale experiment and calculated by numerical simulation. The structure of the hole deflector was parameterized and a geometric model was developed to design the hole deflector track. An empirical model was then established to predict the frictional resistance as a function of the hole deflector structure parameters and an optimization method for designing the hole deflector was proposed. Finally, four types of hole deflectors were optimized using this method. The results show good agreement between the numerical simulation and the experimental data. The model error is within 11.6%. The bend radius R and exit angle β are the key factors affecting the performance of the hole deflector. The validation test was conducted for a case hole deflector (5½ in. casing). The measured frictional resistance was decreased from 31.44 N to 23.16 N by 26.34%. The results from this research could serve as a reference for the design of hole deflectors for radial jet drilling.

scholarly journals Impact Resistance Analysis and Optimization of Variant Truss Beam Structure Based on Material Properties

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5847
Author(s):  
Xiaohao Li ◽  
Junqi Pan ◽  
Xingchen Zhou
Keyword(s):  
Simulation Analysis ◽  
Impact Load ◽  
Impact Resistance ◽  
Structure Design ◽  
Response Surfaces ◽  
Optimization Strategy ◽  
Buffer Effect ◽  
Characteristic Analysis ◽  
Beam Structure ◽  
The Impact

In order to meet the increasing application requirements with regards to structural impact resistance in industries such as mining, construction, aerospace engineering, and disaster relief and mitigation, this paper designs a variant truss beam structure with a large shrinkage ratio and high impact resistance. Based on the principle of the curved trajectory of scissor mechanisms, this paper conducts a finite element simulation analysis of the impact load on the truss beam structure, a theoretical analysis of the impact response and a relevant prototype bench-top experiment, completing a full study on the impact resistance mechanism of the designed variant truss beam structure under the impact load. In the paper, the buffer effect of the external load impact on the variant truss beam structure is analyzed from the perspective of the energy change of elastic–plastic deformation. This paper proposes an optimization strategy for the variant truss beam structure with the energy absorption rate as the optimization index through extensive analysis of the parameter response surfaces. The strategy integrates analyses on the response characteristic analysis of various configuration materials to obtain an optimal combination of component parameters that ensures that the strength of the truss beam structure meets set requirements. The strategy provides a feasible method with which to verify the effectiveness and impact resistance of a variant truss structure design.

Thermoplastique Degradation under Heat and Irradiation

2021 ◽  
Vol 904 ◽  
pp. 196-201
Author(s):  
Sonya Redjala ◽  
Said Azem ◽  
Nourredine Ait Hocine
Keyword(s):  
Mechanical Characteristics ◽  
Low Cost ◽  
Impact Resistance ◽  
Ultra Violet ◽  
Analytical Techniques ◽  
Mechanical Tests ◽  
Ultraviolet Rays ◽  
Technical Material ◽  
Effects Of Temperature ◽  
The Impact

The aim of the article is to highlight the effect of the environment on the properties of a polycarbonate (PC). It consists in aging this material under Ultra-violet (UV) combined with temperature for different periods of time, and to reveal the physicochemical and mechanical changes caused by aging. PC is a highly valued technical material for its various important characteristics and low cost. It finds its application in various fields but mainly in those whose requirements are the transparency and the impact resistance. The physicochemical and mechanicals characterizations of the marketed polycarbonate are necessary in order to highlight its intrinsic properties and to develop strategies that can improve its lifespan. In this work, we highlight the physicochemical and mechanical characteristics of virgin and aged polycarbonate. For this, analytical techniques and mechanical tests were used. A comparison of the characteristics revealed the combined effects of temperature and ultraviolet rays.

K-Means Based Prediction of Transcoded JPEG File Size and Structural Similarity

2012 ◽  
Vol 3 (2) ◽  
pp. 41-57 ◽  
Author(s):  
Steven Pigeon ◽  
Stéphane Coulombe
Keyword(s):  
User Experience ◽  
Low Cost ◽  
Computational Cost ◽  
Structural Similarity ◽  
Perceived Quality ◽  
High Dimensional ◽  
File Size ◽  
Media Access ◽  
Jpeg Images ◽  
Mobile Browsing

The problem of efficiently adapting JPEG images to satisfy given constraints such as maximum file size and resolution arises in a number of applications, from universal media access for mobile browsing to multimedia messaging services. However, optimizing for perceived quality (user experience) commands a non-negligible computational cost which in the authors work, they aim to minimize by the use of low-cost predictors. In previous work, the authors presented predictors and predictor-based systems to achieve low-cost and near-optimal adaption of JPEG images under given constraints of file size and resolution. In this work, they extend and improve these solutions by including more information about images to obtain more accurate predictions of file size and quality resulting from transcoding. The authors show that the proposed method, based on the clustering of transcoding operations represented as high-dimensional vectors, significantly outperforms previous methods in accuracy.

scholarly journals A Novel Approach of Parallel Retina-Like Computational Ghost Imaging

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7093
Author(s):  
Jie Cao ◽  
Dong Zhou ◽  
Fanghua Zhang ◽  
Huan Cui ◽  
Yingqiang Zhang ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Low Cost ◽  
Parallel Architecture ◽  
Structure Design ◽  
Ghost Imaging ◽  
Novel Approach ◽  
Time Correlations ◽  
Long Time ◽  
Sampling And Reconstruction ◽  
Similar Imaging

Computational ghost imaging (CGI), with the advantages of wide spectrum, low cost, and robustness to light scattering, has been widely used in many applications. The key issue is long time correlations for acceptable imaging quality. To overcome the issue, we propose parallel retina-like computational ghost imaging (PRGI) method to improve the performance of CGI. In the PRGI scheme, sampling and reconstruction are carried out by using the patterns which are divided into blocks from designed retina-like patterns. Then, the reconstructed image of each block is stitched into the entire image corresponding to the object. The simulations demonstrate that the proposed PRGI method can obtain a sharper image while greatly reducing the time cost than CGI based on compressive sensing (CSGI), parallel architecture (PGI), and retina-like structure (RGI), thereby improving the performance of CGI. The proposed method with reasonable structure design and variable selection may lead to improve performance for similar imaging methods and provide a novel technique for real-time imaging applications.

scholarly journals On the Use of Biobased Waxes to Tune Thermal and Mechanical Properties of Polyhydroxyalkanoates–Bran Biocomposites

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2615
Author(s):  
Vito Gigante ◽  
Patrizia Cinelli ◽  
Maria Cristina Righetti ◽  
Marco Sandroni ◽  
Giovanni Polacco ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wheat Bran ◽  
Mechanical Performance ◽  
Low Cost ◽  
Impact Resistance ◽  
Mechanical Analysis ◽  
Polymeric Matrix ◽  
Flour Milling ◽  
Mechanical Performances ◽  
Analytic Models

In this work, processability and mechanical performances of bio-composites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing 5, 10, and 15 wt % of bran fibers, untreated and treated with natural carnauba and bee waxes were evaluated. Wheat bran, the main byproduct of flour milling, was used as filler to reduce the final cost of the PHBV-based composites and, in the same time, to find a potential valorization to this agro-food by-product, widely available at low cost. The results showed that the wheat bran powder did not act as reinforcement, but as filler for PHBV, due to an unfavorable aspect ratio of the particles and poor adhesion with the polymeric matrix, with consequent moderate loss in mechanical properties (tensile strength and elongation at break). The surface treatment of the wheat bran particles with waxes, and in particular with beeswax, was found to improve the mechanical performance in terms of tensile properties and impact resistance of the composites, enhancing the adhesion between the PHBV-based polymeric matrix and the bran fibers, as confirmed by predictive analytic models and dynamic mechanical analysis results.

Modified Mechanical Model of Normal Penetration of Rigid Projectiles into an Aluminum Target

2011 ◽  
Vol 323 ◽  
pp. 103-108
Author(s):  
Guang Yan Huang ◽  
Guang Wu ◽  
Shun Shan Feng
Keyword(s):  
Sliding Friction ◽  
Plate Thickness ◽  
Impact Resistance ◽  
Target Material ◽  
Correction Method ◽  
Mechanical Analysis ◽  
Analysis Model ◽  
Rigid Projectile ◽  
Expansion Theory ◽  
Cavity Expansion Theory

Three-stage model of normal penetration of rigid projectile into aluminum plate is developed base on cavity expansion theory (plate thickness is smaller than projectile nose length). Correction method of the models is proposed and predicted results have good agreement with experimental data. The influence of target’s yield stress, target material parameter, sliding friction coefficient and projectile nose shape to penetration process is analyzed through numerical solution. It provides an effective mechanical analysis model for research of projectile impact resistance method to aluminum protective structure.

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