Oblique Penetration of a Circular Pipe Target by a Prefabricated Fragment

2019 ◽  
Vol 19 (10) ◽  
pp. 1950119
Author(s):  
Yajun Wang ◽  
Weibing Li ◽  
Guili Zhu ◽  
Wenbin Li
Keyword(s):  
Initial Velocity ◽  
Critical Angle ◽  
Circular Pipe ◽  
Entry Angle ◽  
Failure Characteristics ◽  
Finite Element Software ◽  
Direction Angle ◽  
The Relationship ◽  
Penetration Velocity ◽  
Good Agreement

For the oblique penetration of a circular pipe target by a prefabricated fragment, the finite element software LS-DYNA was used to build a computational model for the circular pipe considering the penetration by a cylindrical fragment from different directions. The failure characteristics of the pipe were acquired and the critical penetration velocity was calculated. The relationship between the initial velocity and critical angle of ricochet was found. The experiment was then conducted to verify the results obtained, indicating that the simulation results are in good agreement with the experimental ones. It was shown that the main critical failure pattern of a circular pipe is shear perforation or a penetrating crack. The critical penetration velocity is positively correlated with the direction angle [Formula: see text] and entry angle [Formula: see text]. For entry angles greater than 30∘, the critical penetration velocity increases with an increase in the direction angle, and this effect is stronger for higher direction angles. The critical angle of ricochet is positively correlated with the initial velocity of the fragment. The critical angle of ricochet tends to approach a constant of 60∘ as the initial velocity of the fragment increases.

Numerical Test Research on High-Strength Concrete Square Columns with High-Strength Aseismic Transverse Reinforcement under Concentric Compression

2015 ◽  
Vol 1120-1121 ◽  
pp. 1475-1479
Author(s):  
Hui Ding ◽  
Jian Ping Wang ◽  
Li Song
Keyword(s):  
High Strength Concrete ◽  
Numerical Test ◽  
Volume Ratio ◽  
High Strength ◽  
Concrete Columns ◽  
Transverse Reinforcement ◽  
Strength Concrete ◽  
Finite Element Software ◽  
The Relationship ◽  
Good Agreement

This paper focuses on the the relationship between strength and ductility of high-strength concrete (HSC) columns with high-strength aseismic transverse reinforcement under concentric compression and its influencing factors. Some confining models for HSC with high-strength aseismic transverse reinforcement are introduced. Based on 10 groups of high-strength aseismic stirrup confined high-strength concrete square columns are tested under concentric compression, the influence of stirrup in binding strength and the ductility of concrete columns on different stirrup strength, different volume ratio of reinforcement, different stirrups type and different stirrup spacing form is studied by using finite element software ABAQUS. The results indicate that a good agreement is obtained between calculated results and experimental ones. The high-strength stirrup confined concrete columns can improve the bearing capacity and deformation performance of components effectively, laying the foundation of the applications of high-strength stirrups in concrete structures.

Collapse of Sharp-Notched 6061-T6 Aluminum Alloy Tubes Under Cyclic Bending

2016 ◽  
Vol 16 (07) ◽  
pp. 1550035 ◽  
Author(s):  
Chen-Cheng Chung ◽  
Kuo-Long Lee ◽  
Wen-Fung Pan
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Cyclic Bending ◽  
Finite Element Software ◽  
Buckling Failure ◽  
Simulation Results ◽  
Number Of Cycles ◽  
The Moment ◽  
The Relationship ◽  
Good Agreement

The mechanical behavior and buckling failure of sharp-notched 6061-T6 aluminum alloy tubes with different notch depths subjected to cyclic bending are experimentally and theoretically investigated. The experimental moment–curvature relationship exhibits an almost steady loop from the beginning of the first cycle. However, the ovalization–curvature relationship exhibits a symmetrical, increasing, and ratcheting behavior as the number of cycles increases. The six groups of tubes tested have different notch depths, from which two different trends can be observed from the relationship between the controlled curvature and the number of cycles required to ignite buckling. Finite element software ANSYS is used to simulate the moment–curvature and ovalization–curvature relationships. Additionally, a theoretical model is proposed for simulation of the controlled curvature-number of cycles concerning the initiation of buckling. Simulation results are compared with experimental test data, which shows generally good agreement.

Numerical Capacity Examination of RC Beams Subjected to Partial Rebar Corrosion

2016 ◽  
Vol 707 ◽  
pp. 60-71 ◽  
Author(s):  
Yi Zhou Yang ◽  
Lu Kuan Qi
Keyword(s):  
Steel Corrosion ◽  
Absorption Capacity ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Energy Absorption Capacity ◽  
Rc Structures ◽  
Finite Element Software ◽  
Corrosion Rates ◽  
The Relationship ◽  
Good Agreement

Steel Corrosion affects severely on the life and durability of RC structures. In order to investigate the relationship between partial corrosion of RC beams and its cracking morphology and flexural capacity, based on experimental data, RC partial corrosion beam models are simulated using finite element software to model the flexural cracks and capacity of corroded RC beam under different corrosion rates. The results of compared analysis with experiment are presented: with the increase of the corrosion rate, the cracking region is almost consistent, the number of cracks reduces gradually, crack spacing becomes more unequal, bending stiffness and yield strength greatly reduce, ultimate flexural capacity and energy absorption capacity deteriorates, numerical simulation results are in good agreement with experiment.

scholarly journals Experimental studies on the transformation from firn to ice in the wet-snow zone of temperate glaciers

1997 ◽  
Vol 24 ◽  
pp. 181-185 ◽  
Author(s):  
Katsuhisa Kawashima ◽  
Tomomi Yamada
Keyword(s):  
Experimental Studies ◽  
Ice Formation ◽  
Compression Tests ◽  
Densification Rate ◽  
Overburden Pressure ◽  
Proportionality Constant ◽  
Wet Snow ◽  
Water Saturated ◽  
The Relationship ◽  
Good Agreement

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.

Estimation of Interlayer Thickness in Inorganic Particulate-Filled Polymer Composites

2011 ◽  
Vol 24 (6) ◽  
pp. 777-788 ◽  
Author(s):  
J.Z. Liang
Keyword(s):  
Polymer Composites ◽  
Volume Fraction ◽  
Particle Diameter ◽  
Interfacial Structure ◽  
Interlayer Thickness ◽  
Filled Polymer ◽  
Mechanical And Physical Properties ◽  
The Relationship ◽  
Good Agreement

The structure of the interlayer between matrix and inclusions affect directly the mechanical and physical properties of inorganic particulate-filled polymer composites. The interlayer thickness is an important parameter for characterization of the interfacial structure. The effects of the interlayer between the filler particles and matrix on the mechanical properties of polymer composites were analyzed in this article. On the basis of a simplified model of interlayer, an expression for estimating the interlayer thickness ([Formula: see text]) was proposed. In addition, the relationship between the [Formula: see text] and the particle size and its concentration was discussed. The results showed that the calculations of the [Formula: see text] and thickness/particle diameter ratio ([Formula: see text]) increased nonlinearly with an increase of the volume fraction of the inclusions. Moreover, the predictions of [Formula: see text] and the relevant data reported in literature were compared, and good agreement was found between them.

TCAD Study of the Raised SiGe Source/Drain in 40nm PMOS

2015 ◽  
Vol 645-646 ◽  
pp. 70-74 ◽  
Author(s):  
Min Zhong ◽  
Yu Hang Zhao ◽  
Shou Mian Chen ◽  
Ming Li ◽  
Shao Hai Zeng ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Critical Role ◽  
Sige Layer ◽  
Strain Engineering ◽  
Effect Transistor ◽  
Simulation Results ◽  
Aided Design ◽  
The Relationship ◽  
Growth Experiments ◽  
Good Agreement

An embedded SiGe layer was applied in the source/drain areas (S/D) of a field-effect transistor to boost the performance in the p channels. Raised SiGe S/D plays a critical role in strain engineering. In this study, the relationship between the SiGe overfilling and the enhancement of channel stress was investigated. Systematic technology computer aided design (TCAD) simulations of the SiGe overfill height in a 40 nm PMOS were performed. The simulation results indicate that a moderate SiGe overfilling induces the highest stress in the channel. Corresponding epitaxial growth experiments were done and the obtained experimental data was in good agreement with the simulation results. The effect of the SiGe overfilling is briefly discussed. The results and conclusions presented within this paper might serve as useful references for the optimization of the embedded SiGe stressor for 40 nm logic technology node and beyond.

Phase stability, Debye temperature and hardness of semiconducting manganese tetraboride MnB4: First-principles investigations

2017 ◽  
Vol 31 (20) ◽  
pp. 1750131 ◽  
Author(s):  
Ming-Min Zhong ◽  
Cheng Huang ◽  
Chun-Ling Tian
Keyword(s):  
Debye Temperature ◽  
Phase Stability ◽  
First Principles ◽  
Formation Enthalpy ◽  
Structural Features ◽  
High Melting Point ◽  
Fundamental Understanding ◽  
New Perspective ◽  
The Relationship ◽  
Good Agreement

First-principles investigations are employed to provide a fundamental understanding of the structural features, phase stability, mechanical properties, Debye temperature, and hardness of manganese tetraboride. Eight candidate structures of known transition-metal tetraborides are chosen to probe. The calculated lattice parameters, elastic properties, Poisson’s ratio, and [Formula: see text] ratio are derived. It is observed that the monoclinic structure with [Formula: see text] symmetry (MnB4–MnB4) is the most stable in energy. The mechanical and thermodynamic stabilities of seven possible phases are confirmed by the calculated elastic constants and formation enthalpy. Moreover, the analysis on density of states demonstrates semiconducting behavior of MnB4–MnB4 and different metallic behaviors of other phases. The estimated hardness of MnB4–MnB4 is 38.3 GPa, which is in good agreement with experimental value. Furthermore, the relationship between hardness and Debye temperature is investigated and verifies that MnB4–MnB4 is a newly potential semiconducting ultrahard material with high melting point. It provides a new perspective of searching for semiconducting superhard materials to be applied in extreme conditions.

Estimating the influence of temperature on the survival of chinook salmon smolts (Oncorhynchus tshawytscha) migrating through the Sacramento – San Joaquin River Delta of California

1995 ◽  
Vol 52 (4) ◽  
pp. 855-863 ◽  
Author(s):  
Peter Fritz Baker ◽  
Franklin K. Ligon ◽  
Terence P. Speed
Keyword(s):  
Water Temperature ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Logistic Function ◽  
Laboratory Findings ◽  
Natural Systems ◽  
San Joaquin River ◽  
Influence Of Temperature On ◽  
The Relationship ◽  
Good Agreement

Data from the U.S. Fish and Wildlife Service are used to investigate the relationship between water temperature and survival of hatchery-raised fall-run chinook salmon (Oncorhynchus tshawytscha) smolts migrating through the Sacramento – San Joaquin Delta of California. A formal statistical model is presented for the release of smolts marked with coded-wire tags (CWTs) in the lower Sacramento River and the subsequent recovery of marked smolts in midwater trawls in the Delta. This model treats survival as a logistic function of water temperature, and the release and recovery of different CWT groups as independent mark–recapture experiments. Iteratively reweighted least squares is used to fit the model to the data, and simulation is used to establish confidence intervals for the fitted parameters. A 95% confidence interval for the upper incipient lethal temperature, inferred from the trawl data by this method, is 23.01 ± 1.08 °C This is in good agreement with published experimental results obtained under controlled conditions (24.3 ± 0.1 and 25.1 ± 0.1 °C for chinook salmon acclimatized to 10 and 20 °C, respectively): this agreement has implications for the applicability of laboratory findings to natural systems.

Numerical Simulation of Compressive Residual Strength for Damaged Composite Laminates

2012 ◽  
Vol 525-526 ◽  
pp. 385-388
Author(s):  
Tian Jiao Qu ◽  
Xi Tao Zheng ◽  
Di Zhang
Keyword(s):  
Composite Laminates ◽  
Impact Test ◽  
Compressive Load ◽  
Low Velocity Impact ◽  
Fiber Breakage ◽  
Low Velocity ◽  
Appearance Time ◽  
Finite Element Software ◽  
Set Up ◽  
Good Agreement

After the low-velocity impact test of composite laminates of T800/BA9916, CAI test and compression test of laminates with a hole have been carried out. Two types of models were set up by the finite element software ABAQUS respectively. The FEA results were good agreement with the testing results. The investigation of models with a hole indicates that the appearance time of ultimate compressive load is earlier than that of fiber breakage expanding to boundary. Moreover, the diameter and the depth of blind hole significantly influence the ultimate compressive load.

scholarly journals Fatigue Performance of Thin Laser Butt Welds in HSLA Steel

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1499
Author(s):  
Patricio G. Riofrío ◽  
Fernando Antunes ◽  
José Ferreira ◽  
António Castanhola Batista ◽  
Carlos Capela
Keyword(s):  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Hsla Steel ◽  
High Strength ◽  
Butt Joints ◽  
Factors Affecting ◽  
Weld Profile ◽  
The Relationship ◽  
Good Agreement ◽  
Significant Factors

This work is focused on understanding the significant factors affecting the fatigue strength of laser-welded butt joints in thin high-strength low-alloy (HSLA) steel. The effects of the weld profile, imperfections, hardness, and residual stresses were considered to explain the results found in the S-N curves of four welded series. The results showed acceptable fatigue strength although the welded series presented multiple-imperfections. The analysis of fatigue behavior at low stress levels through the stress-concentrating effect explained the influence of each factor on the S-N curves of the welded series. The fatigue limits of the welded series predicted through the stress-concentrating effect and by the relationship proposed by Murakami showed good agreement with the experimental results.

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