Low Velocity Impact of an Elastic Plate Resting on Sand

1988 ◽  
Vol 55 (4) ◽  
pp. 887-894 ◽  
Author(s):  
H. L. Chen ◽  
W. Lin ◽  
L. M. Keer ◽  
S. P. Shah
Keyword(s):  
Half Space ◽  
Wave Speed ◽  
Impact Load ◽  
Radial Strain ◽  
Elastic Half Space ◽  
Low Velocity Impact ◽  
Target Plate ◽  
Low Velocity ◽  
Soil Response ◽  
Velocity Impact

This article describes the measurement and analysis of plate and soil response under low velocity impact. A free-drop impact system was developed to generate the dynamic loading on the plate free surface. The radial strain of the target plate, the longitudinal wave speed and the acceleration of the sand were measured. The measured wave speed data were then used to evaluate the elastic constants of the sand. An analysis based on linear elastodynamics was developed for transient waves on a thin plate resting on an elastic half space. The contact stresses and the normal displacements of the plate were taken as unknown functions. The contact between the plate and the half space were assumed frictionless. The experimental results of the radial strain at the bottom of the target plate and the acceleration of the sand beneath the center of the target plate were compared with the analytical solution. The arrival time, the duration, and the magnitude have good correlation between the analysis and experiment. The overall results appear good and provide an understanding of the transmission of impact load through the plate, the interaction between the plate and the sand, and the propagation of the load into the sand.

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 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.

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 Low-Velocity Impact Resistance of Al/Gf/PP Laminates with Different Interface Performance

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4416
Author(s):  
Yanyan Lin ◽  
Huaguan Li ◽  
Zhongwei Zhang ◽  
Jie Tao
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Impact Load ◽  
Rear Surface ◽  
Impact Resistance ◽  
Nitrogen Plasma ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

The weak interface performance between metal and composite (IPMC) makes the composite materials susceptible to impact load. Aluminum/glass fiber/polypropylene (Al/Gf/PP) laminates were manufactured with the aluminum alloy sheets modified by nitrogen plasma surface treatment and the phosphoric acid anodizing method, respectively. FEM models of Al/Gf/PP laminates under low-velocity impact were established in ABAQUS/Explicit based on the generated data including the model I and II interlaminar fracture toughness. Low-velocity impact tests were performed to investigate the impact resistance of Al/Gf/PP laminates including load traces, failure mechanism, and energy absorption. The results showed that delamination was the main failure mode of two kinds of laminates under the impact energy of 20 J and 30 J. When the impact energy was between 40 J and 50 J, there were metal cracks on the rear surface of the plasma pretreated specimens, which possessed higher energy absorption and impact resistance, although the integrity of the laminates could not be preserved. Since the residual compressive stress was generated during the cooling process, the laminates were more susceptible to stretching rather than delamination. For impact energy (60 J) causing the through-the-thickness crack of two kinds of laminates, plasma pretreated specimens exhibited higher SEA values close to 9 Jm2/kg due to better IPMC. Combined with the FEM simulation results, the interface played a role in stress transmission and specimens with better IPMC enabled the laminates to absorb more energy.

scholarly journals Impact Response and Damage Characteristics of Carbon Fiber Reinforced Aluminum Laminates Under Low Velocity Impact Loading

2020 ◽  
Vol 9 (4) ◽  
pp. 1831-1837
Keyword(s):  
Impact Energy ◽  
Impact Load ◽  
Three Dimensional ◽  
Low Velocity Impact ◽  
Fe Model ◽  
Low Velocity ◽  
Fiber Layer ◽  
Cross Sectional ◽  
Velocity Impact ◽  
The Impact

CARALL hybrid material has been extensively used in the aircraft structure due to their competitive impact strength. Low velocity impact test is utilized to evaluate the impact and damage properties for such material. It is also employed to observe complex damage mechanisms. A numerical modelling is an alternative way for impact assessment. This paper investigates the impact and damage properties under low velocity impact using numerical modeling and experimental work. A three-dimensional (3D) finite element (FE) model was devolved and validated with two studies from the literature. This model was meshed with solid elements. It was subjected to 2.4 m/s impact velocity and to 10 J impact energy. Absorbed energy, penetration, impact load and damage morphology were obtained. The impact energy was efficiently absorbed by the material. Both aluminum alloy layers underwent plastic deformation whereas the fiber layer failed. A macroscopic cross-sectional morphology was presented using the FE model. An agreement between the numerical and the experiment results were achieved and discussed.

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