scholarly journals FLEXURAL REINFORCED CONCRETE MEMBERS WITH MINIMUM REINFORCEMENT UNDER LOW-VELOCITY IMPACT LOAD

2018 ◽  
Vol 14 (46) ◽  
Author(s):  
Warakorn Tantrapongsaton
Keyword(s):  
Reinforced Concrete ◽  
Impact Load ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Minimum Reinforcement ◽  
Concrete Members

Recommendations for Designing Reinforced Concrete Beams Against Low Velocity Impact Loads

2018 ◽  
Vol 18 (09) ◽  
pp. 1850104 ◽  
Author(s):  
Piyapong Wongmatar ◽  
Chayanon Hansapinyo ◽  
Vanissorn Vimonsatit ◽  
Wensu Chen
Keyword(s):  
Reinforced Concrete ◽  
Impact Load ◽  
Reaction Force ◽  
Reinforced Concrete Beams ◽  
Low Velocity Impact ◽  
Inertia Force ◽  
Impact Loads ◽  
Rc Beams ◽  
Low Velocity ◽  
Velocity Impact

This study investigates the behaviors of simply supported reinforced concrete (RC) beams subjected to impact loads. A numerical model of RC beams has been calibrated and a total of 18 RC beams with varying longitudinal reinforcement, transverse shear reinforcement, span and effective depth are investigated, subjected to different input impact energy. It is found that inertia force plays an important role in resisting an impact load at the starting time. The slenderness of the beam can cause increased downward reaction force and also amplifies the upward reaction force. Based on the numerical results, recommendations are made for designing RC beams under low velocity impact load. A formula is derived to predict the maximum mid-span deflection under low velocity impact load with respect to the kinetic energy and static bending capacity. The maximum spacing and the diameter of stirrups are also recommended so as to avoid the brittle failure under impact load.

scholarly journals Mechanical Characterization and Impact Damage Assessment of Hybrid Three-Dimensional Five-Directional Composites

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1395 ◽  
Author(s):  
Liwei Wu ◽  
Wei Wang ◽  
Qian Jiang ◽  
Chunjie Xiang ◽  
Ching-Wen Lou
Keyword(s):  
Carbon Fiber ◽  
Impact Load ◽  
Hybrid Composites ◽  
Impact Damage ◽  
Three Dimensional ◽  
Low Velocity Impact ◽  
Aramid Fibers ◽  
Braided Composites ◽  
Low Velocity ◽  
Velocity Impact

The effects of braided architecture and co-braided hybrid structure on low-velocity response of carbon-aramid hybrid three-dimensional five-directional (3D5d) braided composites were experimentally investigated in this study. Low-velocity impact was conducted on two types of hybridization and one pure carbon fiber braided reinforced composites under three velocities. Damage morphologies after low-velocity impact were detected by microscopy and ultrasonic nondestructive testing. Interior damages of composites were highly dependent on yarn type and alignment. Impact damage tolerance was introduced to evaluate the ductility of hybrid composites. Maximum impact load and toughness changed with impact velocity and constituent materials of the composites. The composite with aramid fiber as axial yarn and carbon fiber as braiding yarn showed the best impact resistance due to the synergistic effect of both materials. Wavelet transform was applied in frequency and time domain analyses to reflect the failure mode and mechanism of hybrid 3D5d braided composites. Aramid fibers were used either as axial yarns or braiding yarns, aiding in the effective decrease in the level of initial damage. In particular, when used as axial yarns, aramid fibers effectively mitigate the level of damage during damage evolution.

scholarly journals Low-Velocity Impact Load Testing of RC Beams Strengthened in Flexure with Bonded FRP Sheets

2020 ◽  
Vol 24 (5) ◽  
pp. 04020036 ◽  
Author(s):  
Norimitsu Kishi ◽  
Masato Komuro ◽  
Tomoki Kawarai ◽  
Hiroshi Mikami
Keyword(s):  
Impact Load ◽  
Low Velocity Impact ◽  
Rc Beams ◽  
Load Testing ◽  
Low Velocity ◽  
Velocity Impact

Impact Energy for the First Crack of Reinforced Concrete with Partial Replacements of Sand by Fine Crumb Rubber

2013 ◽  
Vol 701 ◽  
pp. 286-290 ◽  
Author(s):  
Mustafa Maher Al-Tayeb ◽  
B.H. Abu Bakar ◽  
Hanafi Ismail ◽  
Hazizan Md Akil
Keyword(s):  
Reinforced Concrete ◽  
Impact Energy ◽  
Impact Loading ◽  
Crumb Rubber ◽  
Low Velocity Impact ◽  
Moist Air ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

Effects of partial replacements of sand by waste fine crumb rubber on the performance of reinforced concrete under low velocity impact loading were investigated. Specimens were prepared for 5%, 10% and 20 % replacements by volume of sand. All specimens were cured in moist air for 90 days. For each case, six beams of 100 mm ×100 mm × 500mm were subjected to 5.15 kg hammer from 900mm height. The number of blows of the hammer required to induce the first visible crack of the beam were recorded. The results are presented in terms of impact energy required for the first crack. The fine crumb rubbers increased the impact energy for first crack.

Impact Behaviour of Woven Natural Silk Composite Face-Sheet Sandwiched Foam under Low Velocity Impact

2013 ◽  
Vol 774-776 ◽  
pp. 1242-1249 ◽  
Author(s):  
Albert U. Ude ◽  
Ahmad K. Ariffin ◽  
Che H. Azhari
Keyword(s):  
Impact Load ◽  
Energy Levels ◽  
Low Velocity Impact ◽  
Face Sheet ◽  
Low Velocity ◽  
Velocity Impact ◽  
Natural Silk ◽  
Damage Initiation ◽  
The Impact ◽  
Composite Face

This paper describes the result of an experimental investigation on the impact damage on woven natural silk/epoxy composite face-sheet and PVC foam core sandwich panel. The test panels were prepared by hand-lay-up method. The low-velocity impact response of the composites sandwich panels is studied at three energy levels of 32, 48, and 64 joule respectively. The focus is to investigate damage initiation, damage propagation, and mechanisms of failure. It was observed that absorption energy capability decreased as impact energy increased. There was deflection on each impact load configuration at some point but their margin was insignificant. Physical examination of the specimen show that damage areas increased with increase in impact load. The novelty of this research is the use of woven natural silk fabric as a reinforcement fibre.

Dynamic response of circular GLARE fiber—metal laminates subjected to low velocity impact

2011 ◽  
Vol 30 (11) ◽  
pp. 978-987 ◽  
Author(s):  
George J. Tsamasphyros ◽  
George S. Bikakis
Keyword(s):  
Differential Equations ◽  
Dynamic Response ◽  
Impact Load ◽  
Equations Of Motion ◽  
Time History ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Fiber Metal Laminates ◽  
Velocity Impact ◽  
Fiber Metal

This article deals with the dynamic response of thin circular clamped GLARE fiber—metal laminates subjected to low velocity impact by a lateral hemispherical impactor. Using a spring-mass model, the differential equations of motion corresponding to loading and unloading stages of impact are derived and solved numerically. Internal damage due to delamination is taken into account. Previously published analytical formulas1,2 concerning the indentation of circular GLARE plates are used during the loading stages of impact. In this study, an equation for the unloading path is derived and used during the unloading impact stage. The load—time, position—time, velocity—time, and kinetic energy—time history responses are calculated. In this regard, the position where delamination occurs, the maximum plate deformation and the position where the impact load becomes zero are predicted. Also, the maximum impact load and the total impact duration are determined. The derived differential equations of motion are applied for GLARE 4-3/2 and GLARE 5-2/1 circular plates subjected to low velocity impact. The predicted load—time history response is compared with published experimental data and a good agreement is found. No other solution of this problem is known to the authors.

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