Investigation of rain erosion on a brittle material by means of numerical simulation

2011 ◽  
Vol 9 (4) ◽  
pp. 327-334
Author(s):  
H Anıl Salman ◽  
R Orhan Yıldırım
Keyword(s):  
Brittle Material ◽  
Plate Thickness ◽  
Material Model ◽  
Float Glass ◽  
Water Jet ◽  
Arbitrary Lagrangian Eulerian ◽  
Arbitrary Lagrangian Eulerian Method ◽  
Maximum Water ◽  
Water Speed ◽  
Rain Erosion

In this work, the resistance and deformation characteristics of a brittle material against rain erosion are examined by using the non-linear, explicit software LS-DYNA. The water jet with varying speeds impinges at 90° on silica float glass plates with different thicknesses. In the simulations, the Arbitrary Lagrangian Eulerian method is used for modelling of the water. In order to analyse the deformations on the brittle material Johnson–Holmquist–Ceramics (JH-2) is used as the material model. Minimum plate thickness (for constant water jet speed) and maximum water speed (for constant plate thickness), which do not cause any damage to the target, are determined depending on the geometry, boundary conditions and assumed failure strain value for erosion. The results are compared with the water-hammer pressure.

Damage Analysis and Simulation of Rock under High Pressure Waterjet

2011 ◽  
Vol 462-463 ◽  
pp. 774-779
Author(s):  
Hu Si ◽  
Xiao Hong Li ◽  
Yan Ming Xie
Keyword(s):  
High Pressure ◽  
Damage Mechanics ◽  
Water Jet ◽  
Penalty Function Method ◽  
Impulsive Effect ◽  
Contact Method ◽  
Arbitrary Lagrangian Eulerian ◽  
Rock Breakage ◽  
Pressure Water ◽  
High Pressure Water Jet

The high pressure waterjet is widely applied for mine industry, mechanical manufacture, environmental engineering, and medicine field due to its particular characteristic. Recently, the application of high pressure waterjet for gas drainage in mine has been receiving increasing attention with the development of exploitative technology. The micro-damage mechanism of coal under high pressure water jet is key to drain gas effectively. Based on damage mechanics and rock dynamics, the paper analyzed the micro-structure deformation and damage of rock and the impulsive effect under high pressure water jet and developed the dynamic model. Further, on the assumption of that rock was homogeneous and isotropic, a computational model was established based on the Arbitrary Lagrangian Eulerian (ALE) fluid-solid coupling penalty function method. The rock damage under high pressure water jet was simulated by the dynamic contact method. The results showed that the damage and breakage of ruck was mainly attributed to impacting effect and was characterized by local effect, and the evolvement of rock breakage went through three stages and the figure of rock breakage trended a funnel. On the whole, numerical results agreed with experimental results.

scholarly journals A Useful Manufacturing Guide for Rotary Piercing Seamless Pipe by ALE Method

2020 ◽  
Vol 8 (10) ◽  
pp. 756
Author(s):  
Ameen Topa ◽  
Burak Can Cerik ◽  
Do Kyun Kim
Keyword(s):  
Numerical Simulations ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Material Model ◽  
Manufacturing Processes ◽  
Arbitrary Lagrangian Eulerian ◽  
Analysis Method ◽  
Seamless Pipe ◽  
Ale Formulation ◽  
Good Agreement

The development of numerical simulations is potentially useful in predicting the most suitable manufacturing processes and ultimately improving product quality. Seamless pipes are manufactured by a rotary piercing process in which round billets (workpiece) are fed between two rolls and pierced by a stationary plug. During this process, the material undergoes severe deformation which renders it impractical to be modelled and analysed with conventional finite element methods. In this paper, three-dimensional numerical simulations of the piercing process are performed with an arbitrary Lagrangian–Eulerian (ALE) formulation in LS-DYNA software. Details about the material model as well as the elements’ formulations are elaborated here, and mesh sensitivity analysis was performed. The results of the numerical simulations are in good agreement with experimental data found in the literature and the validity of the analysis method is confirmed. The effects of varying workpiece velocity, process temperature, and wall thickness on the maximum stress levels of the product material/pipes are investigated by performing simulations of sixty scenarios. Three-dimensional surface plots are generated which can be utilized to predict the maximum stress value at any given combination of the three parameters.

scholarly journals A Fast and Accurate Method for Computing the Microwave Heating of Moving Objects

2020 ◽  
Vol 10 (8) ◽  
pp. 2985
Author(s):  
Min Zhang ◽  
Xiubo Jia ◽  
Zhixiang Tang ◽  
Yixuan Zeng ◽  
Xuejiao Wang ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Moving Objects ◽  
Computing Time ◽  
Accurate Method ◽  
High Energy ◽  
Good Choice ◽  
Heating Process ◽  
Arbitrary Lagrangian Eulerian ◽  
Dielectric Parameters ◽  
Arbitrary Lagrangian Eulerian Method

In this paper, we show a fast and accurate numerical method for simulating the microwave heating of moving objects, which is still a challenge because of its complicated mathematical model simultaneously coupling electromagnetic field, thermal field, and temperature-dependent moving objects. By contrast with most discrete methods whose dielectric parameters of the heated samples are updated only when they move to a new position or even turn a circle, in our simulations a real-time procedure is added to renew the parameters during the whole heating process. Furthermore, to avoid the mesh-mismatch induced by remeshing the moving objects, we move the cavity instead of samples. To verify the efficiency and accuracy, we compared our method with the arbitrary Lagrangian–Eulerian method, one of the most accurate methods for computing this process until now. For the same computation model, our method helps in decreasing the computing time by about 90% with almost the same accuracy. Moreover, the influence of the rotational speed on the microwave heating is systematically investigated by using this method. The results show the widely used speed in domestic microwave ovens, 5 rpm, is indeed a good choice for improving the temperature uniformity with high energy efficiency.

Dynamic damage assessment of float glass under blast loading

2019 ◽  
Vol 22 (11) ◽  
pp. 2517-2529
Author(s):  
Xiao-Qing Zhou ◽  
Ming-Yu Wang ◽  
Li-Xiao Li
Keyword(s):  
Damage Assessment ◽  
High Speed ◽  
Blast Loading ◽  
Material Model ◽  
The United States ◽  
Float Glass ◽  
Dynamic Responses ◽  
Kinematic Equation ◽  
Finite Element Software ◽  
Dynamic Damage

Architectural glass, especially the float glass, is a fragile part of a building. The architectural glass becomes a large amount of high-speed flying debris under bomb attacks and accidental explosions, thereby causing serious threat to residents. This study investigates the dynamic responses of a normal float glass subjected to blast loading using the explicit dynamic finite element software LS-DYNA. A JH-2 material model, which considers the strain rate effect and damage accumulation, is adopted for the float glass. A preliminary study shows that the present numerical model combined with reasonable material parameters can simulate the failure mode of the glass and the ejection velocity of glass fragments after failure. The verified model is then used to investigate the dynamic damage responses of the float glass under different loading cases. The damage assessment criterion of float glass is established on the basis of the glazing protection levels defined by the General Services Administration of the United States. Comprehensive simulations are conducted on different amounts of explosive and standoff distances. The degrees of glass damage under different loading cases are determined by combining the projection velocity of glass fragments after failure with a kinematic equation. Finally, the damage assessment diagram of float glass under different amounts of explosive is presented and compared with those in FEMA 426.

Alternative Mesh Refinement Methods for Analysing Soil Penetration Problems

2016 ◽  
Vol 846 ◽  
pp. 415-420
Author(s):  
M.H. Moavenian ◽  
Majidreza Nazem ◽  
John Phillip Carter
Keyword(s):  
Soil Layer ◽  
Deformation Analysis ◽  
Deep Penetration ◽  
Arbitrary Lagrangian Eulerian ◽  
The Finite Element Method ◽  
Mesh Distortion ◽  
B Splines ◽  
Arbitrary Lagrangian Eulerian Method ◽  
Complex Boundary ◽  
Free Falling

Despite recent advances in the finite element method, mesh distortion due to large deformations may still occur in some problems such as footings subjected to deep penetration or objects penetrating into a soil layer. In order to overcome mesh distortion, robust remeshing techniques are required. In this paper the performance of four remeshing methods is studied by analysing a free falling penetrometer penetrating into an undrained layer of soil. These techniques are implemented within the framework of the Arbitrary Lagrangian-Eulerian method and include the refinement based on an elastic relocation, a technique based on the Radial Basis Functions, the Spring Analogy method, and the Elastic Hardening method. Since one of the challenging problems in a large deformation analysis is dealing with complex boundary shapes, a scheme based on the B-Splines used in isogeometric analysis is also presented here.

FE Modeling of the Three-Layer Human Carotid Artery Under Impact Loadings

2007 ◽  
Author(s):  
Aihong Zhao ◽  
Ken Digges ◽  
Mark Field ◽  
David Richens
Keyword(s):  
Finite Element ◽  
Carotid Artery ◽  
Model Simulation ◽  
Material Model ◽  
Element Model ◽  
Traumatic Rupture ◽  
Aortic Tissue ◽  
Fe Model ◽  
Arbitrary Lagrangian Eulerian ◽  
The Impact

Blunt traumatic rupture of the carotid artery is a rare but life threatening injury. The histology of the artery is key to understanding the aetiology of this injury. The carotid artery is composed of three layers known as the tunica intima, media, and adventitia, with distinct biomechanical properties. In order to examine the behaviour of the carotid artery under external load we have developed a three layer finite element model of this vessel. A rubber-like material model from LS-DYNA was selected for the FE model. The Arbitrary-Lagrangian Eulerian (ALE) approach was adopted to simulate the interaction between the fluid (blood) and the structure (carotid). To verify the FE model, the impact bending tests are simulated using this FE model. Simulation results agree with tests results well. Furthermore, the mechanical behaviour of carotid artery tissues under impact loading were revealed by the simulations. The results provide a basis for a more in-depth investigation of the carotid artery in vehicle crashes. In addition, it provides a basis for further work on aortic tissue finite element modeling.

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