Hypervelocity Impact on Concrete and Sandstone: Momentum Enhancement from Tests and Hydrocode Simulations

2019 ◽  
Author(s):  
Sidney Chocron ◽  
James D. Walker ◽  
Donald J. Grosch ◽  
Stephen R. Beissel ◽  
Daniel D. Durda ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Size Effect ◽  
Hypervelocity Impact ◽  
Material Models ◽  
Lawrence Livermore Laboratory ◽  
Impact Tests ◽  
Natural Geometry ◽  
Previous Round ◽  
The Impact

Abstract Concrete, sandstone, and, in a previous round of experiments, pumice, were tested under hypervelocity impact at SwRI. Aluminum spheres with diameters of 1 and 1.75 in were shot at a velocity of approximately 2 km/s using a 50-mm conventional powder gun. The targets were mounted on a swing so that the momentum enhancement could be measured. The size effect, i.e. comparing momentum enhancement generated by the small and large projectiles, was of particular interest in this project. The targets were also scaled, although for sandstone we were limited by the natural geometry of the rocks. The results from the experiments show a clear size effect for the concrete while sandstone did not show any size effect, possibly because of experimental artifacts. The sandstone behavior was investigated with computations using the EPIC hydrocode. The porosity and compressive strength of the sandstone used in the impact tests were measured and reported. The rock is very similar to one reported and extensively tested by Lawrence Livermore Laboratory in 1974. Two material models (Holmquist-Johnson Concrete and Johnson-Holmquist-Beissel) were fit to the data from LLL. The momentum enhancement predicted by the code is reported for different parameter studies.

A Hypervelocity Impact Facilities Based on Double-Barreled Two-Stage Light Gas Gun

2013 ◽  
Vol 834-836 ◽  
pp. 825-828
Author(s):  
Jun Yin ◽  
Yu Wang Yang ◽  
Xia Yun Hu ◽  
Cheng Cheng Yong
Keyword(s):  
Optical Method ◽  
Hypervelocity Impact ◽  
Two Stage ◽  
Impact Speed ◽  
Impact Tests ◽  
Gas Gun ◽  
Almost All ◽  
The Impact

For almost all materials the hypervelocity regime has been reached when the impact speed above 2 km/s. A double-barreled two-stage light gas gun (TSLGG) system used for the hypervelocity impact tests is described. The proposed TSLGG can accelerate 50 g projectile masses up to velocities of 2.2 km/s. The craters produced with this equipment reach a diameter of up to 20 cm, a size unique in laboratory cratering research. The experiment results show our TSLGG system work effectively, velocity of the projectile mass is measured highly accurate by means of the proposed optical method.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

scholarly journals Mechanical Behavior of Hydroxyapatite-Chitosan Composite: Effect of Processing Parameters

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 213
Author(s):  
Hamid Ait Said ◽  
Hassan Noukrati ◽  
Hicham Ben Youcef ◽  
Ayoub Bayoussef ◽  
Hassane Oudadesse ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Compressive Strength ◽  
Mechanical Strength ◽  
Bone Repair ◽  
Mechanical Stability ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Composite Effect ◽  
Solid Liquid ◽  
The Impact

Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of the polymer on the composite mechanical strength was investigated. An increase in the S/L ratio from 0.5 to 1 resulted in an increase in the compressive strength for HA-CSL (CS low molecular weight: CSL) from 0.08 ± 0.02 to 1.95 ± 0.39 MPa and from 0.3 ± 0.06 to 2.40 ± 0.51 MPa for the HA-CSM (CS medium molecular weight: CSM). Moreover, the increase in the amount (1 to 5 wt%) and the molecular weight of the polymer increased the mechanical strength of the composite. The highest compressive strength value (up to 2.40 ± 0.51 MPa) was obtained for HA-CSM (5 wt% of CS) formulated at an S/L of 1. The dissolution tests of the HA-CS composites confirmed their cohesion and mechanical stability in an aqueous solution. Both polymer and apatite are assumed to work together, giving the synergism needed to make effective cylindrical composites, and could serve as a promising candidate for bone repair in the orthopedic field.

scholarly journals Experimental Study on the Mechanical Properties and Compression Size Effect of Recycled Aggregate Concrete

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2323
Author(s):  
Yubing Du ◽  
Zhiqing Zhao ◽  
Qiang Xiao ◽  
Feiting Shi ◽  
Jianming Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Size Effect ◽  
Compressive Stress ◽  
Failure Modes ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Substitution Ratio ◽  
The Impact

To explore the basic mechanical properties and size effects of recycled aggregate concrete (RAC) with different substitution ratios of coarse recycled concrete aggregates (CRCAs) to replace natural coarse aggregates (NCA), the failure modes and mechanical parameters of RAC under different loading conditions including compression, splitting tensile resistance and direct shear were compared and analyzed. The conclusions drawn are as follows: the failure mechanisms of concrete with different substitution ratios of CRCAs are similar; with the increase in substitution ratio, the peak compressive stress and peak tensile stress of RAC decrease gradually, the splitting limit displacement decreases, and the splitting tensile modulus slightly increases; with the increase in the concrete cube’s side length, the peak compressive stress of RAC declines gradually, but the integrity after compression is gradually improved; and the increase in the substitution ratio of the recycled aggregate reduces the impact of the size effect on the peak compressive stress of RAC. Furthermore, an influence equation of the coupling effect of the substitution ratio and size effect on the peak compressive stress of RAC was quantitatively established. The research results are of great significance for the engineering application of RAC and the strength selection of RAC structure design.

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.

scholarly journals Fire Resistance Behaviour of Geopolymer Concrete:An Overview

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 82
Author(s):  
Salmabanu Luhar ◽  
Demetris Nicolaides ◽  
Ismail Luhar
Keyword(s):  
Compressive Strength ◽  
Thermal Resistance ◽  
Building Materials ◽  
Elevated Temperatures ◽  
Construction Materials ◽  
Flexural Behavior ◽  
Thermal Shrinkage ◽  
Physico Chemical ◽  
The Impact ◽  
Loss Of Strength

Even though, an innovative inorganic family of geopolymer concretes are eye-catching potential building materials, it is quite essential to comprehend the fire and thermal resistance of these structural materials at a very high temperature and also when experiencing fire with a view to make certain not only the safety and security of lives and properties but also to establish them as more sustainable edifice materials for future. The experimental and field observations of degree of cracking, spalling and loss of strength within the geopolymer concretes subsequent to exposure at elevated temperature and incidences of occurrences of disastrous fires extend an indication of their resistance against such severely catastrophic conditions. The impact of heat and fire on mechanical attributes viz., mechanical-compressive strength, flexural behavior, elastic modulus; durability—thermal shrinkage; chemical stability; the impact of thermal creep on compressive strength; and microstructure properties—XRD, FTIR, NMR, SEM as well as physico-chemical modifications of geopolymer composites subsequent to their exposures at elevated temperatures is reviewed in depth. The present scientific state-of-the-art review manuscript aimed to assess the fire and thermal resistance of geopolymer concrete along with its thermo-chemistry at a towering temperature in order to introduce this novel, most modern, user and eco-benign construction materials as potentially promising, sustainable, durable, thermal and fire-resistant building materials promoting their optimal and apposite applications for construction and infrastructure industries.

scholarly journals Predicting the behavior of reinforced concrete columns confined by fiber reinforced polymers using data mining techniques

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Sahar Y. Ghanem ◽  
Heba Elgazzar
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Compressive Stress ◽  
Compressive Strain ◽  
Concrete Columns ◽  
Steel Reinforcement ◽  
Fiber Reinforced Polymers ◽  
Stress And Strain ◽  
Fiber Reinforced ◽  
The Impact

AbstractFiber Reinforced Polymer (FRP) usage to wrap reinforced concrete (RC) structures has become a popular technology. Most studies about RC columns wrapped with FRP in literature ignored the internal steel reinforcement. This paper aims to develop a model for the axial compressive strength and axial strain for FRP confined concrete columns with internal steel reinforcement. The impact of FRP, Transverse, and longitudinal reinforcement is studied. Two non-destructive analysis methods are explored: Artificial Neural Networks (ANNs) and Regression Analysis (RA). The database used in the analysis contains the experimental results of sixty-four concrete columns under the compressive concentric load available in the literature. The results show that both models can predict the column's compressive stress and strain reasonably with low error and high accuracy. FRP has the highest effect on the confined compressive stress and strain compared to other materials. While the longitudinal steel actively contributes to the compressive strength, and the transverse steel actively contributes to the compressive strain.

Effect of toughened polyamide-coated carbon fiber fabric on the mechanical performance and fracture toughness of CFRP

2021 ◽  
pp. 002199832199945
Author(s):  
Jong H Eun ◽  
Bo K Choi ◽  
Sun M Sung ◽  
Min S Kim ◽  
Joon S Lee
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Photoelectron Spectroscopy ◽  
Mechanical Performance ◽  
Epoxy Composites ◽  
Scanning Calorimetry ◽  
Internal Damage ◽  
Impact Tests ◽  
Flexural Tests ◽  
The Impact

In this study, carbon/epoxy composites were manufactured by coating with a polyamide at different weight percentages (5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%) to improve their impact resistance and fracture toughness. The chemical reaction between the polyamide and epoxy resin were examined by fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy. The mechanical properties and fracture toughness of the carbon/epoxy composites were analyzed. The mechanical properties of the carbon/epoxy composites, such as transverse flexural tests, longitudinal flexural tests, and impact tests, were investigated. After the impact tests, an ultrasonic C-scan was performed to reveal the internal damage area. The interlaminar fracture toughness of the carbon/epoxy composites was measured using a mode I test. The critical energy release rates were increased by 77% compared to the virgin carbon/epoxy composites. The surface morphology of the fractured surface was observed. The toughening mechanism of the carbon/epoxy composites was suggested based on the confirmed experimental data.

The impact of carboxylic acid type hydrophobic agent on compressive strength of cementitious materials

2021 ◽  
Vol 291 ◽  
pp. 123315
Author(s):  
Hao Zhang ◽  
Song Mu ◽  
Jingshun Cai ◽  
Ruixing Chen
Keyword(s):  
Compressive Strength ◽  
Carboxylic Acid ◽  
Cementitious Materials ◽  
Acid Type ◽  
Hydrophobic Agent ◽  
The Impact

scholarly journals The Impact of Traffic-Induced Bridge Vibration on Rapid Repairing High-Performance Concrete for Bridge Deck Pavement Repairs

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Wang ◽  
Shuo Liu ◽  
Qizhi Wang ◽  
Wei Yuan ◽  
Mingzhang Chen ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Bridge Deck ◽  
High Performance Concrete ◽  
Reduction Rate ◽  
Harmonic Vibration ◽  
Hydration Reaction ◽  
Self Healing ◽  
The Impact ◽  
Bridge Deck Pavement

Based on forced vibration tests for high-performance concrete (HPC), the influence of bridge vibration induced by traveling vehicle on compressive strength and durability of HPC has been studied. It is concluded that 1 d and 2 d compressive strength of HPC decreased significantly, and the maximum reduction rate is 9.1%, while 28 d compressive strength of HPC had a slight lower with a 3% maximal drop under the action of two simple harmonic vibrations with 2 Hz, 3 mm amplitude, and 4 Hz, 3 mm amplitude. Moreover, the vibration had a slight effect on the compressive strength of HPC when the simple harmonic vibration had 4 Hz and 1 mm amplitude; it is indicated that the amplitude exerts a more prominent influence on the earlier compressive strength with the comparison of the frequency. In addition, the impact of simple harmonic vibration on durability of HPC can be ignored; this shows the self-healing function of concrete resulting from later hydration reaction. Thus, the research achievements mentioned above can contribute to learning the laws by which bridge vibration affects the properties of concrete and provide technical support for the design and construction of the bridge deck pavement maintenance.

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