An Impact Damage Model of Concrete

1985 ◽  
Vol 64 ◽  
Author(s):  
A. S. Kobayashi ◽  
N. M. Hawkins ◽  
J. J. Du
Keyword(s):  
Reasonable Agreement ◽  
Fracture Criterion ◽  
Impact Damage ◽  
Process Zone ◽  
Damage Model ◽  
Plain Concrete ◽  
Element Model ◽  
Dynamic Finite Element ◽  
Average Crack ◽  
Point Bend

ABSTRACTDynamic fracture of two impact loaded, plain concrete, three-point bend specimens was simulated using a dynamic finite element model. A three-segment fracture process zone, which was established in a previous static analysis, together with a tensile overload fracture criterion were used to propagate the crack from the tension side of the unnotched beams. Reasonable agreement between the measured and computed velocities at two points on one beam and estimated and computed average crack velocities was obtained.

Prediction of Impact Damage of Composite Laminates Using a Mixed Damage Model

2014 ◽  
Vol 513-517 ◽  
pp. 235-237
Author(s):  
Shi Yang Zhao ◽  
Pu Xue
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Failure Modes ◽  
Impact Damage ◽  
Damage Model ◽  
Material Model ◽  
Element Model ◽  
Fiber Damage ◽  
Damage Process ◽  
Matrix Damage

In order to effectively describe the damage process of composite laminates and reduce the complexity of material model, a mixed damage model based on Linde Criteria and Hashin Criteria is proposed for prediction of impact damage in the study. The mixed damage model can predict baisc failure modes, including fiber fracture, matrix tensile damage, matrix compressive damage. Fiber damage and matrix damage in compression are described based on the progressive damage mechanics; and matrix damage in tension is described based on Continuous Damage Mechanics (CDM). Meanwhile, for interlaminar delamination, damage is described by cohesive model. A finite element model is established to analyze the damage process of composite laminate. A good agreement is got between damage predictions and experimental results.

Mixed Modes I and II Concrete Fracture: An Experimental Analysis

1994 ◽  
Vol 61 (4) ◽  
pp. 815-821 ◽  
Author(s):  
Z. K. Guo ◽  
A. S. Kobayashi ◽  
N. M. Hawkins
Keyword(s):  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Crack Opening ◽  
Concrete Specimen ◽  
Element Model ◽  
Dissipated Energy ◽  
Mixed Mode Fracture ◽  
Aggregate Interlocking ◽  
Point Bend

The development of the fracture process zone associated with subcritical crack growth in a three-point bend concrete specimen with an off-centered, single-edged precrack was monitored with moire interferometry. The applied load and the crack opening and sliding displacements together with a finite element model of the concrete specimen were used to determine the crack closing stress due to aggregate bridging. Under this mixed-mode fracture, aggregate interlocking increased the crack closing stresses in the fracture process zone and hence the load carrying capacity of the concrete specimen. The dissipated energy rate in the fracture process zone also increased with aggregate interlocking.

Experimental analysis of crack evolution in concrete by the acoustic emission technique

2015 ◽  
Author(s):  
J. Saliba ◽  
A. Loukili ◽  
J.P. Regoin ◽  
D. Grégoire ◽  
L. Verdon ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Process Zone ◽  
Mouth Opening ◽  
Acoustic Emissions ◽  
Plain Concrete ◽  
Crack Mouth Opening Displacement ◽  
Notch Depth ◽  
Opening Displacement ◽  
Magnitude Distribution

The fracture process zone (FPZ) was investigated on unnotched and notched beams with different notch depths. Three point bending tests were realized on plain concrete under crack mouth opening displacement (CMOD) control. Crack growth was monitored by applying the acoustic emission (AE) technique. In order to improve our understanding of the FPZ, the width and length of the FPZ were followed based on the AE source locations maps and several AE parameters were studied during the entire loading process. The bvalue analysis, defined as the log-linear slope of the frequency-magnitude distribution of acoustic emissions, was also carried out to describe quantitatively the influence of the relative notch depth on the fracture process. The results show that the number of AE hits increased with the decrease of the relative notch depth and an important AE energy dissipation was observed at the crack initiation in unnotched beams. In addition, the relative notch depth influenced the AE characteristics, the process of crack propagation, and the brittleness of concrete.

Impact of a Fixed-Length Rigid Cylinder on an Elastic-Plastic Homogeneous Body

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou
Keyword(s):  
Impact Damage ◽  
Element Model ◽  
Elastic Behavior ◽  
Magnetic Storage ◽  
Practical Case ◽  
Homogeneous Body ◽  
Rigid Cylinder ◽  
Elastic Plastic ◽  
Fixed Length ◽  
The Impact

A contact mechanics (CM) based model of a fixed-length rigid cylinder impacting a homogeneous elastic-plastic homogeneous body was developed and includes an improved method of estimating the residual depth after impact. The nonlinear elastic behavior during unloading was accounted for to develop an improved coefficient of restitution model. The impact model was applied to study a practical case of a cylindrical feature on the slider of a magnetic storage hard disk drive impacting the disk to predict various critical impact contact parameters. The CM model was validated using a plane strain finite element model and it was found that a cylindrical feature with a longer length results in a substantial alleviation of impact damage.

Parameter Study of Concrete Impact Damage Model Based on DOE Analysis

2012 ◽  
Vol 502 ◽  
pp. 451-457
Author(s):  
Jiang Bo Wang ◽  
Qing Ming Zhang ◽  
Cheng Liang Feng ◽  
Wei Bing Li ◽  
Heng Wang
Keyword(s):  
Impact Velocity ◽  
Impact Damage ◽  
Damage Model ◽  
Considerable Effect ◽  
Model Material ◽  
Parameter Study ◽  
Material Parameters ◽  
Model Based ◽  
Two Parameters ◽  
The Impact

By building up a debugging method about material parameters of concrete impact damage model based on DOE (Design of Experiments) analysis, this paper studies the influence of material parameters of concrete targets on the results of numerical simulation based on quantitative analysis, when the impact velocity is 300m/s and 850m/s respectively. It concludes that when the impact velocity of 300m/s, 5 parameters have considerable effect on the residual velocity of warhead, they are ， ， ， and . Of all 5 parameters, , and can be obtained by calculation therefore it only needs to debug two parameters and according to experiments. Finally, when the impact velocity is 300m/s or so, debug combining the experiments to get a set of concrete impact damage model material parameters to make the results of simulation and experiment anastomosis well.

Simulation of Impact Damage in Foam-Based Sandwich Composites

2013 ◽  
Vol 569-570 ◽  
pp. 25-32
Author(s):  
Dian Shi Feng ◽  
Francesco Aymerich
Keyword(s):  
Impact Damage ◽  
Element Model ◽  
Fracture Mechanisms ◽  
Sandwich Composites ◽  
Typically Developing ◽  
Damage Resistance ◽  
Damage And Fracture ◽  
Closed Cell ◽  
Impact Energies ◽  
The Impact

The paper describes the application of a 3D finite element model for prediction of impact induced damage in sandwich composites consisting of laminated skins bonded to a closed cell foam core. The major damage and fracture mechanisms typically developing in transversally loaded sandwich composites were simulated in the model. The model was implemented in the FE package ABAQUS/Explicit and used to predict the impact damage resistance of sandwich panels with different core densities, core thicknesses, and skins layups. Numerical results obtained by FE simulations were compared with experimental data and observations collected through impact tests carried out at various impact energies.

High Velocity Oblique Impact and Coefficient of Restitution for Head Disk Interface Operational Shock

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Jorge V. Hanchi ◽  
Robert M. Crone
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Impact Damage ◽  
Element Model ◽  
Oblique Impact ◽  
Coefficient Of Restitution ◽  
Energy Losses ◽  
Elastic Plastic ◽  
Impact Angles ◽  
Operational Shock

With the increased use of hard disk drives (HDDs) in mobile and consumer applications combined with the requirement of higher areal density, there is enhanced focus on reducing head disk spacing, and consequently there is higher susceptibility of slider/disk impact damage during HDD operation. To investigate this impact process, a dynamic elastic-plastic finite element model of a sphere (representing a slider corner) obliquely impacting a thin-film disk was created to study the effect of the slider corner radius and the impact velocity on critical contact parameters. To characterize the energy losses due to the operational shock impact damage, the coefficient of restitution for oblique elastic-plastic impact was studied using the finite element model. A modification to an existing physics-based elastic-plastic oblique impact coefficient of restitution model was proposed to accurately predict the energy losses for a rigid sphere impacting a half-space. The analytical model results compared favorably to the finite element results for the range from low impact angles (primarily normal impacts) to high impact angles (primarily tangential impacts).

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