scholarly journals Numerical Study on the Entrance Effect of Penetration into Concrete Targets

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Huawei Yang ◽  
Ji-wei Luo ◽  
Jie Zhang ◽  
Pei-wen Zhang
Keyword(s):  
Numerical Study ◽  
Construction Material ◽  
Time History ◽  
Target Strength ◽  
Depth Of Penetration ◽  
Entrance Effect ◽  
Predrilled Hole ◽  
Modified Formula ◽  
The Impact ◽  
Penetration Depths

Investigation on penetration into concrete targets is of great importance as concrete is widely used as the fundamental construction material. To achieve a more accurate prediction of penetration depths of concrete targets, a further study was conducted to explore the entrance effect by using AUTODYN hydrocode in this study. The numerical results on both deceleration-time history and depth of penetration of projectiles are in good agreement with experimental data, which demonstrate the feasibility of the numerical model in these conditions. A new target model was established with a predrilled hole around the symmetry axis to simulate the entrance effect of the crater phase on the penetration process. Compared with the regular target, the predrilled target enters the peak of acceleration earlier, leading to the reduction of the depth of penetration. In addition, simulation results indicated that nose shape significantly influenced crater region depth, while the depth was independent of the impact velocity and the target strength. Based on the simulation of entrance effect, a modified formula of penetration depth has been proposed and validated in terms of different nose shapes. The crater region depths obtained from the simulations can improve the accuracy of the predictions of the penetration depths for the penetration of concrete targets.

Numerical Study of High Velocity Impact onto MMC/Ceramic Layered Systems

2016 ◽  
Vol 715 ◽  
pp. 210-215
Author(s):  
Seung Hwan Lee ◽  
Minh Lee
Keyword(s):  
Mild Steel ◽  
Ceramic Tile ◽  
Volume Fraction ◽  
Numerical Study ◽  
Tungsten Alloy ◽  
Layered Systems ◽  
Depth Of Penetration ◽  
Ballistic Performance ◽  
Long Rod ◽  
The Impact

Metal Matrix Composites (MMCs) can be applied to military applications due to the light weight and the ballistic performance. In this study, a numerical simulation has been performed for the penetration of a long-rod penetrator into MMC/Ceramic layered systems. The impact velocity is 1.5km/s and the length to diameter (L/D) ratio is 10.6. First, the ballistic performances of each candidate materials are examined by doing the semi-infinite target simulation to estimate the depth of penetration (DOP) data. The materials included in this study are four (tungsten alloy, mild steel, SiC, MMC. The MMC materials are SiC/Al7075 (volume fraction around 45%). For a reference data, the impact simulation into mild-steel target only was also carried out. Finally, the main simulation is performed by varying the position of ceramic tile at three types of the thickness of ceramic tile. The residual velocity, residual mass and residual kinetic energy of the long-rod are obtained from the simulation. Based on these predicted values, the optimum system of the layered plate has been estimated.

An Estimate for Mass Loss From High Velocity Steel Penetrators

2002 ◽  
Author(s):  
S. E. Jones ◽  
J. C. Foster ◽  
O. A. Toness ◽  
R. J. DeAngelis ◽  
William K. Rule
Keyword(s):  
Mass Loss ◽  
High Velocity ◽  
Areal Density ◽  
Analytical Models ◽  
Target Strength ◽  
Depth Of Penetration ◽  
Tunnel Length ◽  
Simple Estimate ◽  
Penetration Process ◽  
The Impact

Analytical models of the penetration process focus on estimating depth of penetration based on target density, target strength (sometimes associated with the unconfined compressive strength of the target for geological targets), the areal density of the penetrator (W/A), and the impact velocity. In this paper, an expression for work is used in conjunction with thermodynamic considerations to devise a simple estimate for mass lost by a high velocity projectile during the penetration process. The result shows that the mass loss is directly proportional to the tunnel length and the target shear strength. The constant of proportionality is not easy to deduce, however, in that it contains an unusual factor from the work analysis. A method for estimating target shear under high pressure from penetration experiments is introduced.

scholarly journals Seismic Performance Evaluation of a Proposed Buckling-Restrained Brace for RC-MRFS

2019 ◽  
Vol 29 (3) ◽  
pp. 164-173
Author(s):  
Arunraj Ebanesar ◽  
Daniel Cruze ◽  
Ehsan Noroozinejad Farsangi ◽  
Vincent Sam Jebadurai Seenivasan ◽  
Adil Dar Mohammad ◽  
...  
Keyword(s):  
Seismic Performance ◽  
Inner Core ◽  
Numerical Study ◽  
Construction Material ◽  
Time History ◽  
Expanded Polystyrene ◽  
Disaster Mitigation ◽  
Ductile Material ◽  
Conventional Concrete ◽  
Buckling Restrained Brace

Abstract This paper presents a novel buckling-restrained brace (BRB) where the inner core is restrained by a concrete infilled Expanded Polystyrene Sheet (EPS) instead of the conventional concrete infilled tube section, to resist inner core buckling. It serves two purposes, firstly, the EPS is a ductile material, which is favourable in terms of seismic performance and, secondly, the outer construction material has better corrosion resistance. Thus, the life of the steel core can be prolonged. In this study, 6 BRB specimens were prepared, of which 3 BRB specimens were infilled with concrete and the remaining 3 BRB specimens with concrete and EPSs, in order to study their performance under cyclic loading. Three different core heights, all with the same core thickness, were adopted. The test results indicate that the load-carrying capacity of this novel BRB is higher than the conventional BRB. Further, the length of the steel tube also affects the strength of the seismic disaster mitigation system. Lastly, a numerical study on a single bay RC frame, with and without BRB subjected to time history analysis, was conducted to check the global performance of this novel system. It was found that the structural responses had substantially decreased.

Investigation on the Impact and Penetration Performance of the Particulated Jet into Concrete Targets

2019 ◽  
Author(s):  
Qi-feng Zhu ◽  
Qiang-qiang Xiao ◽  
Zheng-xiang Huang ◽  
Xu-dong Zu ◽  
Xin Jia
Keyword(s):  
Titanium Alloys ◽  
Nickel Titanium ◽  
Shaped Charge ◽  
Ti Alloy ◽  
Depth Of Penetration ◽  
Experiment Method ◽  
Coherent Jet ◽  
Shaped Charge Jet ◽  
The Impact ◽  
Penetration Depths

Abstract In this study, the performance of titanium alloys (TC21, TC1), nickel-titanium (Ni-Ti) alloy, and zirconium-niobium (Zr-Nb) alloy lined shaped charge impact and penetration into concrete targets are investigated experimentally. Shaped charge jet radiographs reveal that the resulting jets of titanium alloys and Ni-Ti alloy exhibit particulate, radially dispersed behaviors, whereas that of the Zr-Nb alloy is coherent. Cavity diameters, penetration depths and parameters of the impact craters generated by the jets were analyzed using the depth of penetration (DOP) experiment method. Data indicate that the particulated jet causes more extensive damage to the surface of the concrete targets compared to the coherent jet. The penetration depth decreases to some degree, but the cavity diameter increases significantly. Penetration efficiency varies with degree of dispersion of the particulated jet and, as such, is also sensitive to stand-off distance.

A Numerical Study of TAD and TLP Platforms Operating Side by Side

2020 ◽  
Author(s):  
Bo Tong ◽  
Rui Chang ◽  
Zhuang Kang ◽  
Haibo Sui ◽  
Shaojie Li
Keyword(s):  
Hydrodynamic Interaction ◽  
Numerical Study ◽  
Time History ◽  
Body Motion ◽  
Floating Body ◽  
Mooring Line ◽  
Diffraction Radiation ◽  
Drilling Rig ◽  
Drilling System ◽  
The Impact

Abstract A Tender Assisted Drilling (TAD) is typically a support vessel that serves support of a drilling rig, by offering comfortable accommodation for crew and providing additional space where the Drilling Equipment Set is stored and transported. The operation with TAD provides an economical and flexible way for offshore drilling, especially with TLP. Dynamic response of tender-assisted drilling system is crucial due to the safety concern. However, some urgent issue has not been thoroughly studied in tender assisted drilling operation like the hydrodynamic interaction and the impact of nonlinearity cable used. In this paper, a tender assisted drilling system which was taken as the research object was investigated under the metocean conditions of West Africa. The numerical model was established in frequency domain using 3D multi-body diffraction/radiation wave theory and the hydrodynamic interaction is studied in this part. Then two kinds mull-body system with different hawsers arrangements are analyzed by the time domain simulation was performed considering hydrodynamic interaction and the impact of nonlinearity of mooring lines and hawsers. The Time history results of floating body motion and the force on mooring line is compared between two schemes. The results obtained is also investigated by spectral analysis to clearly understand the coupled behavior of such system under these two arrangement.

scholarly journals Seismic Performance of a Green Roof Structure

2021 ◽  
Vol 13 (8) ◽  
pp. 4278
Author(s):  
Svetlana Tam ◽  
Jenna Wong
Keyword(s):  
Green Roof ◽  
Time History ◽  
Green Roofs ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Roof Structure ◽  
Nonlinear Time History Analyses ◽  
Vegetated Roofs ◽  
Nonlinear Time History ◽  
The Impact

Sustainability addresses the need to reduce the structure’s impact on the environment but does not reduce the environment’s impact on the structure. To explore this relationship, this study focuses on quantifying the impact of green roofs or vegetated roofs on seismic responses such as story displacements, interstory drifts, and floor level accelerations. Using an archetype three-story steel moment frame, nonlinear time history analyses are conducted in OpenSees for a shallow and deep green roof using a suite of ground motions from various distances from the fault to identify key trends and sensitivities in response.

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Review of the relationship between aggregates geology and Los Angeles and micro-Deval tests

2021 ◽  
Vol 80 (3) ◽  
pp. 1963-1980
Author(s):  
Solomon Adomako ◽  
Christian John Engelsen ◽  
Rein Terje Thorstensen ◽  
Diego Maria Barbieri
Keyword(s):  
Los Angeles ◽  
Crystal Size ◽  
Grain Shape ◽  
Mechanical Performance ◽  
Pore Space ◽  
Construction Material ◽  
Engineering Properties ◽  
Coarse Grained ◽  
The Impact ◽  
The Relationship

AbstractRock aggregates constitute the enormous volume of inert construction material used around the globe. The petrologic description as igneous, sedimentary, and metamorphic types establishes the intrinsic formation pattern of the parent rock. The engineering properties of these rocks vary due to the differences in the transformation process (e.g. hydrothermal deposits) and weathering effect. The two most common mechanical tests used to investigate the performance of aggregates are the Los Angeles (LA) and micro-Deval (MD) tests. This study reviewed the geological parameters (including mineralogy, grain and crystal size, grain shape, and porosity) and the relationship to Los Angeles and micro-Deval tests. It was found that high content of primary minerals in rocks (e.g. quartz and feldspar) is a significant parameter for performance evaluation. Traces of secondary and accessory minerals also affect the performance of rocks, although in many cases it is based on the percentage. Furthermore, some studies showed that the effect of mineralogic composition on mechanical strength is not sufficient to draw final conclusions of mechanical performance; therefore, the impact of other textural characteristics should be considered. The disposition of grain size and crystal size (e.g. as result of lithification) showed that rocks composed of fine-grain textural composition of ≤ 1 mm enhanced fragmentation and wear resistance than medium and coarse grained (≥ 1 mm). The effect of grain shape was based on convex and concave shapes and flat and elongated apexes of tested samples. The equidimensional form descriptor of rocks somehow improved resistance to impact from LA than highly flat and elongated particles. Lastly, the distribution of pore space investigated by means of the saturation method mostly showed moderate (R = 0.50) to strong (R = 0.90) and positive correlations to LA and MD tests.

scholarly journals The Impact of Post-Manufacture Treatments on the Surface Characteristics Important for Finishing of OSB and Particleboard

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 975
Author(s):  
Antonio Copak ◽  
Vlatka Jirouš-Rajković ◽  
Nikola Španić ◽  
Josip Miklečić
Keyword(s):  
Water Vapour ◽  
Oriented Strand Board ◽  
Construction Material ◽  
Surface Characteristics ◽  
Surface Treatments ◽  
Factors Affecting ◽  
Treatment Conditions ◽  
Water Vapour Absorption ◽  
The Impact

Oriented strand board (OSB) is a commonly used structural wood-based panel for walls and roof siding, but recently the industry has become interested in OSB as a substrate for indoor and outdoor furniture. Particleboard is mainly used in furniture productions and has become popular as a construction material due to its numerous usage possibilities and inexpensive cost. Moisture is one of the most important factors affecting wood-based panel performance and the post-treatment conditions affected their affinity to water. When OSB and particleboard are used as substrates for coatings, their surface characteristics play an important role in determining the quality of the final product. Furthermore, roughness can significantly affect the interfacial phenomena such as adsorption, wetting, and adhesion which may have an impact on the coating performance. In this research particleboard and OSB panels were sanded, re-pressed and IR heated and the influence of surface treatments on hardness, roughness, wetting, water, and water vapour absorption was studied. Results showed that sanding improved the wetting of particleboard and OSB with water. Moreover, studied surface treatments increased water absorption and water penetration depth of OSB panels, and re-pressing had a positive effect on reducing the water vapour absorption of particleboard and OSB panels.

scholarly journals Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1425
Author(s):  
Tarek Bouzennada ◽  
Farid Mechighel ◽  
Kaouther Ghachem ◽  
Lioua Kolsi
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Numerical Study ◽  
Melting Rate ◽  
Heat Transfer Fluid ◽  
Commercial Code ◽  
Tube Position ◽  
The Impact ◽  
Change Material

A 2D-symmetric numerical study of a new design of Nano-Enhanced Phase change material (NEPCM)-filled enclosure is presented in this paper. The enclosure is equipped with an inner tube allowing the circulation of the heat transfer fluid (HTF); n-Octadecane is chosen as phase change material (PCM). Comsol-Multiphysics commercial code was used to solve the governing equations. This study has been performed to examine the heat distribution and melting rate under the influence of the inner-tube position and the concentration of the nanoparticles dispersed in the PCM. The inner tube was located at three different vertical positions and the nanoparticle concentration was varied from 0 to 0.06. The results revealed that both heat transfer/melting rates are improved when the inner tube is located at the bottom region of the enclosure and by increasing the concentration of the nanoparticles. The addition of the nanoparticles enhances the heat transfer due to the considerable increase in conductivity. On the other hand, by placing the tube in the bottom area of the enclosure, the liquid PCM gets a wider space, allowing the intensification of the natural convection.

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