Real-Time Detection and Explicit Finite Element Simulation of Delamination in Composite Laminates Under Impact Loading

2000 ◽  
Author(s):  
K. Minnaar ◽  
M. Zhou
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Real Time ◽  
Impact Loading ◽  
Matrix Cracking ◽  
Laser Vibrometer ◽  
Zone Model ◽  
Elastic Model ◽  
Damage Initiation ◽  
The Impact

Abstract A new experimental technique is developed to determine the onset and evolution of delamination in fiber-reinforced composites under impact loading. The configuration uses a split-Hopkinson bar for low-velocity impact loading and two Polytec laser vibrometer systems for real-time monitoring of the initiation and progression of delamination. The experiment allows the histories of load, displacement, and velocity of impacted specimens to be recorded and analyzed. The recorded profiles are used to characterize the damage initiation and evolution in the laminate. Numerical simulations are conducted using a cohesive finite element method. The method employs a cohesive zone model to simulate matrix cracking and interlaminar delamination and a transversely isotropic, elastic model to characterize the bulk behavior of each ply. The simulations provide time-resolved characterization of damage during the impact loading. The damage modes predicted by the numerical simulations agree well with experimental observations.

Experimental Characterization and Numerical Simulation of Impact Damage in Composite Laminates

2001 ◽  
Author(s):  
K. Minnaar ◽  
M. Zhou
Keyword(s):  
Impact Loading ◽  
Bonding Strength ◽  
Composite Laminates ◽  
Cohesive Zone Model ◽  
Low Velocity Impact ◽  
Laser Vibrometer ◽  
Zone Model ◽  
Elastic Model ◽  
Low Velocity ◽  
The Impact

Abstract A new experimental technique is developed to determine the onset and evolution of delamination in fiber-reinforced composites. The configuration uses a split-Hopkinson bar for low-velocity impact loading and two Polytec laser vibrometer systems for real-time monitoring of the initiation and progression of delamination. The experiment allows the histories of load, displacement, and velocity of impacted specimens to be recorded and analyzed. Numerical simulations are conducted using a cohesive finite element method. The method employs a cohesive zone model to simulate in-ply cracking and interlaminar delamination and a transversely isotropic, elastic model to characterize the bulk behavior of each ply. The simulations provide time-resolved characterization of damage during the impact loading. The time at which delamination is detected decreases as the impact velocity is increased, and delamination is detected at similar surface displacements. The progression of damage changes as the bonding strength between plies is increased. The speed of delamination decreases as the bonding strength is increased.

Experimental and Numerical Plastic Response and Failure of Laterally Impacted Rectangular Plates

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
B. Liu ◽  
R. Villavicencio ◽  
C. Guedes Soares
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Failure Modes ◽  
Mesh Size ◽  
Plastic Behavior ◽  
Finite Element Models ◽  
Rectangular Plates ◽  
Marine Structures ◽  
Fine Mesh ◽  
The Impact

Experimental and numerical results of drop weight impact test are presented on the plastic behavior and fracture of rectangular plates stuck laterally by a mass with a hemispherical indenter. Six specimens were tested in order to study the influence of the impact velocity and the diameter of the indenter. The impact scenarios could represent abnormal actions on marine structures, such as ship collision and grounding or dropped objects on deck structures. The tests are conducted on a fully instrumented impact tester machine. The obtained force-displacement response is compared with numerical simulations, performed by the LS-DYNA finite element solver. The simulations aim at proposing techniques for defining the material and restraints on finite element models which analyze the crashworthiness of marine structures. The mesh size and the critical failure strain are predicted by numerical simulations of the tensile tests used to obtain the mechanical properties of the material. The experimental boundary conditions are modeled in order to represent the reacting forces developed during the impact. The results show that the critical impact energy until failure is strongly sensitive to the diameter of the striker. The shape of the failure modes is well predicted by the finite element models when a relatively fine mesh is used. Comments on the process of initiation and propagation of fracture are presented.

scholarly journals New CZM for Interfacial Crack Growth

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Huifen Peng ◽  
Yujie Song ◽  
Ye Xia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Growth ◽  
Interface Crack ◽  
Interfacial Crack ◽  
Structure Design ◽  
Zone Model ◽  
Simulation Results ◽  
The Impact ◽  
Element Method

The cohesive zone model (CZM) has been widely used for numerical simulations of interface crack growth. However, geometrical and material discontinuities decrease the accuracy and efficiency of the CZM when based on the conventional finite element method (CFEM). In order to promote the development of numerical simulation of interfacial crack growth, a new CZM, based on the wavelet finite element method (WFEM), is presented. Some fundamental issues regarding CZM of interface crack growth of double cantilever beam (DCB) testing were studied. The simulation results were compared with the experimental and simulation results of CFEM. It was found that the new CZM had higher accuracy and efficiency in the simulation of interface crack growth. At last, the impact of crack initiation length and elastic constants of material on interface crack growth was studied based on the new CZM. These results provided a basis for reasonable structure design of composite material in engineering.

Finite-Element Modeling and Model Verification of Steel W-Beam Guardrails Subject to Pendulum Impact Loading

1998 ◽  
Vol 1647 (1) ◽  
pp. 147-157
Author(s):  
T. Russell Gentry ◽  
Lawrence C. Bank
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
Model Verification ◽  
Federal Highway ◽  
Time Histories ◽  
Tension Capacity ◽  
The Impact ◽  
Impact Events ◽  
Pendulum Impact ◽  
Good Agreement

The experimental and simulated response of steel W-beam guards to pendulum impact loading for impact velocities of 20 km/h, 30 km/h, and 35 km/h are presented. The guardrails were supported by four posts and cable-anchored at each end to ensure that the full tension capacity of the rail could be developed. Experiments carried out with a 912-kg impact pendulum are compared with LS-DYNA finite-element simulations of the impact events. Pendulum tests were completed at the Turner Fairbank Highway Research Center of the Federal Highway Administration. Acceleration, velocity, and displacement time histories are compared for the pendulum impact test and the LS-DYNA simulations. Comparison of the experimental and simulation acceleration records is made using the Numerical Analysis of Roadside Design time-domain statistics. The comparative statistics show that the simulations are in good agreement with the experiments. Guardrail tension data and cable tension data are presented from the LS-DYNA simulations. Results show that the guardrail was close to its tension yield point when impacted an initial velocity of 35 km/h.

scholarly journals Collapse Behaviour of a Concrete-Filled Steel Tubular Column Steel Beam Frame under Impact Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lian Song ◽  
Hao Hu ◽  
Jian He ◽  
Xu Chen ◽  
Xi Tu
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
Mechanical Performance ◽  
Impact Load ◽  
Frame Structure ◽  
Actual Condition ◽  
Transverse Impact ◽  
Time Curve ◽  
Finite Element Software ◽  
The Impact

The progressive collapse of a concrete-filled steel tubular (CFST) frame structure is studied subjected to impact loading of vehicle by the finite-element software ABAQUS, in the direct simulation method (DS) and alternate path method (AP), respectively. Firstly, a total of 14 reference specimens including 8 hollow steel tubes and 6 CFST specimens were numerically simulated under transverse impact loading for verification of finite-element models, which were compared with the existing test results, confirming the overall similarity between them. Secondly, a finite-element analysis (FEA) model is established to predict the impact behaviour of a five-storey and three-span composite frame which was composed of CFST columns and steel beams under impact vehicle loading. The failure mode, internal force-time curve, displacement-time curve, and mechanical performance of the CFST frame were obtained through analyzing. Finally, it is concluded that the result by the DS method is closer to the actual condition and the collapse process of the structure under impact load can be relatively accurately described; however, the AP method is not.

scholarly journals Relationship Between Matrix Cracking and Delamination in CFRP Cross-Ply Laminates Subjected to Low Velocity Impact

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3990 ◽  
Author(s):  
Riming Tan ◽  
Jifeng Xu ◽  
Wei Sun ◽  
Zhun Liu ◽  
Zhidong Guan ◽  
...  
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Matrix Cracks ◽  
Impact Location ◽  
The Matrix ◽  
The Impact

The effect of matrix cracking on the delamination morphology inside carbon fiber reinforced plastics (CFRP) laminates during low-velocity impact (LVI) is an open question. In this paper, the relationship between matrix cracking and delamination is studied by using cross-ply laminates. Several methods, including micrograph, C-scan, and visual inspection, were adopted to characterize the damage after LVI experiments. Based on the experimental results, finite element (FE) models were established to analyze the damage mechanisms. The matrix cracking was predicted by the extended finite element method (XFEM) and the Puck criteria, while the delamination was modeled by cohesive elements. It was revealed that the matrix crack in the bottom ply not only promoted the outward propagation of delamination but also contributed to the narrow delamination beneath the impact location. Multiple matrix cracks occurred in the middle ply. The ones close to the plate center initiated the delamination and prevented large-scale delamination beneath the impact location. For the cracks that were far away, no significant effect on delamination was found. In conclusion, the stress redistribution caused by the crack opening determines the delamination.

Experimental Study on Impact Resistance of Dump Truck Bodies Floor

2014 ◽  
Vol 1051 ◽  
pp. 857-861
Author(s):  
Bin Tian ◽  
Da Wei Liu ◽  
Long Long Zhu
Keyword(s):  
Finite Element Method ◽  
Experimental Study ◽  
Finite Element ◽  
Impact Loading ◽  
Impact Resistance ◽  
Test System ◽  
Dump Truck ◽  
Stress Variation ◽  
Metal Materials ◽  
The Impact

In order to study the impact resistance capability of dump truck bodies floor, a simulation model of dump truck bodies floor and impact hammerheads made of metal materials were designed, and a strain test system of bodies floor under impact loading was established, a measurement of the stress of bodies floor model was made to obtain the law of stress variation about key point of truck bodies floor model. The research laid the foundation for the analysis of impact resistance capability of dump truck bodies floor using finite element method as well as provided a reference for the structural optimization of truck bodies floor.

Experimental and numerical study of reinforced concrete beams with steel fibers subjected to impact loading

2017 ◽  
Vol 27 (7) ◽  
pp. 1058-1083 ◽  
Author(s):  
Liu Jin ◽  
Renbo Zhang ◽  
Guoqin Dou ◽  
Jiandong Xu ◽  
Xiuli Du
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Impact Loading ◽  
Impact Force ◽  
Numerical Study ◽  
Reaction Force ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
The Impact

As a kind of impact resistant material, steel fiber reinforced concrete (SFRC) has a good ductility and energy dissipation capacity by improving the tensile strength and impact toughness. To explore the dynamic mechanical behavior of SFRC beams subjected to impact loading, 12 simply-supported SFRC beams with different stirrup ratios (0%, 0.253% and 0.502%) and different volume fractions of steel fibers (0%, 1%, 2% and 3%) were tested with free-falling drop-weights impacting at the mid-span of specimens. The failure patterns were observed and videoed, and simultaneously, the time histories of the impact force, the reaction force, and the mid-span deflection were recorded. Moreover, the influences of stirrup ratio and volume fraction of steel fibers on the impact resistant behavior of the SFRC beams were preliminarily analyzed and discussed. The results indicate that the impact resistant performance of SFRC beams, such as crack pattern, ductility, energy consumption capacity, and deformation recovery capacity can be improved by the addition of steel fibers and stirrups. The required static capacity of these beams were calculated based on the analysis of reaction force vs. displacement loop and impact force vs. displacement loop as well as absorbed energy ratio. For further understanding the experimental results, finite element simulation of SFRC beams subjected to impact loading were carried out. The rationality and accuracy of the finite element model was illustrated by the good agreement between the test observations and the numerical results.

scholarly journals A Time-Discontinuous Galerkin Finite Element Method for the Solution of Impact Problem of Gas-Saturated Coal

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jingfei Zhang ◽  
Deyong Guo ◽  
Wenhua Wu ◽  
Pan Guo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Discontinuous Galerkin ◽  
Impact Loading ◽  
Galerkin Finite Element Method ◽  
Galerkin Finite Element ◽  
Discontinuous Galerkin Finite Element ◽  
The Impact ◽  
Impact Problem ◽  
Element Method

Based on the general Biot theory of saturated porous media, a modified time-discontinuous Galerkin finite element method (MDGFEM) is presented to simulate the structural dynamics and wave propagation problems of gas-saturated coal subjected to impact loading. Numerical results of one dimension and two dimensions show that the present MDGFEM possesses better abilities and provides much more accurate solutions than the traditional Newmark method and previous DGFEM for the impact problem. It can effectively capture the discontinuities of the wave and filter out the effects of spurious numerical oscillation induced by high-frequency impulsive load. The results can provide a technological basis for the research of the prevention of coal and gas dynamic disasters under deep mining. And the method could be useful for the further numerical research of coal-rock-gas coupling problems and coal-gas-heat coupling problems subjected to impact loading.

Real-Time Finite Element Analysis of a Remotely Operated Pipeline Repair System

2013 ◽  
Author(s):  
Dean M. Steinke ◽  
Ryan S. Nicoll ◽  
André R. Roy
Keyword(s):  
Finite Element ◽  
Real Time ◽  
Simulation Software ◽  
Model Verification ◽  
Pilot Training ◽  
Repair System ◽  
Simulation Framework ◽  
Lumped Mass ◽  
Training Simulator ◽  
The Impact

Remotely operated vehicle (ROV) pilots are frequently trained to operate in increasingly complex subsea environments using ROV simulators. These computer simulators de-risk important subsea operations by increasing ROV pilots’ skill levels in performing tasks under challenging environmental and operational constraints. ROV pilot-training simulation scenarios typically involve a variety of subsea equipment, such as trees, flow lines, pipeline end terminations (PLETs), etc. However, many critical ROV tasks, such as pipeline repair or riser installation, involve flexible structures. The following paper investigates a method for accurately simulating pipelines and flexibles within an ROV pilot-training simulator. The goal of the technology development is to enable engineers and marine operators to assess the risks associated with certain tasks, such as pipeline repair or flexible hook-up, in real-time using ROV simulation technology. In particular, the challenge that this paper will address is how to determine the stresses in a subsea pipeline using a lumped mass finite-element cable model within a multi-body simulation framework. Repair of subsea pipelines is a complex multi-step process typically carried out by ROVs. During pipeline repair, a pipeline repair system (PRS) is lowered to the seabed. The PRS must lift the pipeline off the seabed and the damaged section of pipeline must then be cut and removed, and a new section of pipeline put in place. During the lifting, cutting and installation phases it is important that the pipeline is not overstressed and the equipment used in the repair operation is not overloaded. In addition, there are a wide array of operational variables, procedures and decisions that must be evaluated. Towards this end, an ROV simulation facility capable of assessing stresses and operations in real-time was constructed using the finite element simulation software package ProteusDS in conjunction with GRI Simulations Inc.’s VROV simulator. The system was designed to evaluate the impact of different combinations of operating parameters and is intended to be useful for system design and analysis. The system would be of immense utility in rapid response to a real-world incident where the system may be called into action. The following paper reviews the simulation framework, the models employed, the results of model verification, and discusses the challenges of the project.

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