A Study on Plastic Zones of 3 Point Bend Specimens under Various Impact Velocities

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1349-1354
Author(s):  
Moon Sik Han ◽  
Jae Ung Cho ◽  
Ouk Sub Lee
Keyword(s):  
Impact Load ◽  
Compressive Load ◽  
Material Model ◽  
Static Displacement ◽  
Plastic Zones ◽  
Point Bend ◽  
Displacement Speed ◽  
Von Mises ◽  
The Impact ◽  
Uncertain Boundary

In this paper, computer simulations of the mechanical behavior of 3 point bend (3PB) specimens with a quarter notch under impact load are performed. The cases with various impact velocities applied at the side of the specimen are considered. An elastic-plastic von Mises material model is chosen. Results from no viscoplastic and viscoplastic materials are compared. Their materials are applied with static displacement speed and various impact velocities. The configuration of the specimen has the reduced width at the ends. This modified 3PB specimen design has been studied in order to avoid the initial compressive load of the crack tip and also to avoid the uncertain boundary conditions at the impact heads.

A Study on Three Phases During the Period for Crack Initiation under Impact Load

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1362-1367
Author(s):  
Moon Sik Han ◽  
Jae Ung Cho ◽  
Chang Min Suh
Keyword(s):  
Crack Initiation ◽  
Impact Load ◽  
Plastic Hinge ◽  
Crack Tip ◽  
Material Model ◽  
Second Phase ◽  
Static State ◽  
Von Mises ◽  
The Impact ◽  
Three Phases

Computer simulations of the dynamic behavior of a three point bend specimen under impact load are performed. Two cases with different load application points at the side and at the middle of the specimen are considered. An elastic-plastic von Mises material model is chosen. Three phases such as impact, bouncing and bending phases are found to be identified during the period from the moment of impact to the estimated time for crack initiation. It is clearly shown that no plastic deformation near the crack tip is appeared at the impact phase. However, it is confimted that the plastic zone near the crack tip emerges in the second phase and the plastic hinge has been formed in the third phase i.e., at the end of which a quasi static state is reached.

scholarly journals Drop Simulation of 6M Drum With Locking-Ring Closure and Liquid Contents

2006 ◽  
Author(s):  
Tsu-Te Wu
Keyword(s):  
Impact Load ◽  
Three Dimensional ◽  
Structural Response ◽  
Material Model ◽  
Element Model ◽  
Ring Closure ◽  
Foot Drop ◽  
Torque Load ◽  
Three Dimensional Finite Element ◽  
The Impact

This paper presents the dynamic simulation of the 6M drum with a locking-ring type closure subjected to a 4.9-foot drop. The drum is filled with water to 98 percent of overflow capacity. A three dimensional finite-element model consisting of metallic, liquid and rubber gasket components is used in the simulation. The water is represented by a hydrodynamic material model in which the material’s volume strength is determined by an equation of state. The explicit numerical method based on the theory of wave propagation is used to determine the combined structural response to the torque load for tightening the locking-ring closure and to the impact load due to the drop.

The Effect of SAS Materials and Modeling in Transferring Impact Loads to the Brain

2010 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Brain Injuries ◽  
Impact Load ◽  
Compressive Load ◽  
Impact Loads ◽  
Modeling Methodology ◽  
Wide Range ◽  
The Impact ◽  
The Brain

While subarachnoid space (SAS) trabeculae play an important role in damping and reducing the relative movement of the brain with respect to the skull, thereby reducing traumatic brain injuries, their mechanical properties and modeling are not well established in the literature. A few studies, e.g., Zhang et al. (2002) and Xin Jin et al. (2008) have reported a wide range the elastic modulus of the trabeculae up to three orders of magnitudes. The histology of the trabeculae reveals a collagen based structure. Thus, a few investigators have estimated the mechanical properties of trabeculae based on collagen’s properties. The objective of this study is to determine the stress/strain changes in the brain as a function of the mechanical properties and modeling methodology of the trabeculae, when the loading and the boundary conditions of the model are kept the same. This study was performed through several modeling steps. A wide range of the mechanical properties of the trabeculae was employed and the transductions of blunt impact loads from the skull to the brain were determined. The mechanical properties of the SAS trabeculae were determined based on the validation of the models with experimental results of Sabet et al. (2009). The result indicated that when we use softer material properties for the trabeculae the meningeal layers absorb and damp the impact load. It is also concluded that the material properties of the trabeculae can be simulated by only tension element since the trabeculae buckles with minimal compressive load. Finally, an optimum material property of SAS was proposed.

scholarly journals Numerical and Experimental Stress-Strain Analysis of a Rubber Carousel

TEM Journal ◽  
2021 ◽  
pp. 1662-1667
Author(s):  
Peter Koščák ◽  
Ľubomír Ambriško ◽  
Karol Semrád ◽  
Marasová, Jr. Daniela ◽  
Vladimír Mitrík
Keyword(s):  
Mechanical Load ◽  
Impact Load ◽  
Mechanical Damage ◽  
Strain Analysis ◽  
Material Model ◽  
Stress Strain ◽  
Conveyor Belts ◽  
Optimal Material ◽  
Comparison Of The Results ◽  
The Impact

The effect of the impact load exerted by the baggage impacting light baggage carousels may be manifested as mechanical damage to the carousel as a result of the stress-strain processes. In order to describe the phenomena related to the baggage impact, it is important to monitor the tensile strength of rubber carousels of light conveyor belts intended for the conveyance of baggage at airports. The output of the article is monitoring the mechanical load of the carousel, the comparison of the results thereof with the outputs of the CAE analysis, as well as the determination of the optimal material model and the approximation thereof to the experimental model.

scholarly journals Effect of Impact and Bearing Parameters on Bird Strike with Aero-Engine Fan Blades

2021 ◽  
Vol 12 (1) ◽  
pp. 7
Author(s):  
Bin Wu ◽  
Reza Hedayati ◽  
Zhehua Li ◽  
Mahsa Aghajanpour ◽  
Guichang Zhang ◽  
...  
Keyword(s):  
Material Model ◽  
Von Mises Stress ◽  
Economic Losses ◽  
Bird Strike ◽  
Impact Location ◽  
Aero Engine ◽  
Particle Hydrodynamics ◽  
Bird Impact ◽  
Von Mises ◽  
The Impact

Bird strikes are one major accident for aircraft engines and can inflict heavy casualties and economic losses. In this study, a smoothed particle hydrodynamics (SPH) mallard model has been used to simulate bird impact to rotary aero-engine fan blades. The simulations were performed using the finite element method (FEM) at LS-DYNA. The reliability of the material model and numerical method was verified by comparing the numerical results with Wilberk’s experimental results. The effects of impact and bearing parameters, including bird impact location, bird impact orientation, initial bird velocity, fan rotational speeds, stiffness of the bearing, and the damping of the bearing on the bird impact to aero-engine fan blade are studied and discussed. The results show that both the impact location and bird orientation have significant effects on the bird strike results. Bird impact to blade roots is the most dangerous scenario causing the impact force to reach 390 kN. The most dangerous orientation is the case where the bird’s head is tilted 45° horizontally, which leads to huge fan kinetic energy loss as high as 64.73 kJ. The bird’s initial velocity affects blade deformations. The von Mises stress during the bird strike process can reach 1238 MPa for an initial bird velocity of 225 m/s. The fan’s rotational speed and the bearing stiffness affect the rotor stability significantly. The value of bearing damping has little effect on the bird strike process. This paper gives an idea of how to evaluate the strength of fan blades in the design period.

SIMULATION OF IMPACT BEHAVIOR OF A GLASS YARN

2020 ◽  
Vol 10 (1) ◽  
pp. 10-17
Author(s):  
Larisa CHIPER ◽  
George Ghiocel OJOC ◽  
Lorena DELEANU ◽  
Catalin PIRVU
Keyword(s):  
Impact Load ◽  
Equivalent Stress ◽  
Material Model ◽  
Impact Behavior ◽  
Impact Simulation ◽  
Micro Level ◽  
Impact Protection ◽  
Simulation Results ◽  
Comparative Results ◽  
The Impact

The issue of impact simulation results from the fact that the impact load is unique and the designed system or element is requested not to fail only once or a small number of loadings. Tests for assessments of the degree of impact protection are expensive and numerous because they require a high probability of impact resistence. In the literature, there are models at the micro level (at fiber level), at the meso level (multi-fiber yarns, several fibers or by evaluating the behavior of the fibers to a monobloc yarn, as is the case with this simulation) and at the macro level (the behavior of element or system is done with some equivalences concerning the material model). This paper presents comparative results of the axis and on the edge of a yarn considered monoblock and isotropic to highlight the differences in the mechanisms of destruction of the yarn and in the evolution of the distribution of equivalent stress, highlighting the differences in the simulation of these two cases explains, at least qualitatively, the differences in the behavior of the panels considered identical.

Elasto-Plastic Impact: Non-Linear FEA vs. Experimental Results

1999 ◽  
Author(s):  
Todd C. Werner ◽  
Daniel H. Suchora
Keyword(s):  
Initial Velocity ◽  
Material Model ◽  
Isotropic Hardening ◽  
Analysis Software ◽  
Element Analysis ◽  
Event Simulation ◽  
Linear Finite Element ◽  
Non Linear ◽  
Von Mises ◽  
The Impact

Abstract This paper analyzes the problem of a weight with a specified initial velocity impacting the end of an aluminum cantilever beam. The impact is severe enough to cause significant plastic bending strains in the beam. The impact is modeled using the Algor Event Simulation Non-linear Finite Element Analysis software using 21 node brick elements and a Von-Mises material model with isotropic hardening. Raleigh damping is included in the simulation. The computer generated strain vs. time results are compared to traces obtained from a strain gage instrumented beam subjected to the impact modeled by the software. The comparison of the non-linear FEA computer results and the experimental data shows good correlation.

Thermal Processing History and Resulting Impact Response of a Hot-Formed Component with Tailored Properties – Numerical Study

2014 ◽  
Vol 566 ◽  
pp. 34-40
Author(s):  
Michael J. Worswick ◽  
Ryan George ◽  
Alex Bardelcik ◽  
Luke Ten Kortenaar ◽  
Duane Detwiler
Keyword(s):  
Thermal Processing ◽  
Impact Load ◽  
Numerical Study ◽  
Material Model ◽  
Failure Criteria ◽  
Impact Response ◽  
Sensitive Material ◽  
Forming Simulation ◽  
Processing History ◽  
The Impact

The impact modeling of a hot-formed component with tailored mechanical properties is studied to understand the influence of the thermal processing history and how the final properties of the component will affect its impact response. This paper presents a numerical study of the forming and quenching process and subsequent impact simulations. The processing simulations serve to predict the final microstructure and hardness distribution within a lab-scale B-pillar component that is processed using a tool with separate heated and cooled regions. A remapping algorithm is used to translate the results of the forming simulation to the impact simulation. A strain-rate sensitive material model is applied to model the response of these tailored microstructures during impact events. A comparison between a component that is fully hardened and a tailored component with regions of lower strength but increased ductility is presented in this work. Simulations that do not consider the onset of fracture predict superior peak impact load and energy absorption of the fully martensitic component due to its higher overall strength. However, the bainitic regions within the tailored component exhibit much higher ductility. Current work is addressing the introduction of failure criteria into simulations of tailored hot stamped components under impact loading for which the tailored component is expected to demonstrate superior resistance to cracking relative to the fully hardened component.

Lateral Impact Response of Elliptical Hollow and Partially Concrete-Filled Cold-Formed Steel Columns Under Static Axial Compression Load

2021 ◽  
Author(s):  
Nayyer Mohammadi Rana ◽  
Elham Ghandi ◽  
Shirin Esmaeili Niari
Keyword(s):  
Impact Velocity ◽  
Impact Load ◽  
Impact Resistance ◽  
Compressive Load ◽  
Lateral Impact ◽  
Elliptical Cross ◽  
Compression Load ◽  
Steel Columns ◽  
Size And Shape ◽  
The Impact

In recent years, the use of partially concrete-filled steel tubular (PCFST) columns has been considered due to their cost-effectiveness and reduction of structural weight in bridge piers and building columns. One of the critical discussions about these columns is their impact resistance. In this article, the dynamic response of hollow and PCFST columns with elliptical cross-section under simultaneous loading of static axial compressive load and lateral impact load is presented using finite element modeling in ABAQUS software (FEA). To ensure the accuracy of the numerical modeling, the analysis results are compared with the results of previous works. The effects of different parameters such as impact velocity, the height of the impact location, the impact direction, the impact block mass, the size and shape of the impact block are investigated in this paper. The results of the numerical analysis showed that the partially filled specimens had better performance than the hollow specimens. The changes in impact direction and impact block mass parameters have a significant effect on the failure of the columns, especially when they are under high impact velocity. Changing the impact velocity significantly affects the impact resistance of specimens. However, the size and shape of the impact block did not have a significant effect on the displacement of the column against the impact loading.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

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