scholarly journals Development and Validation of Overpressure Response Model in Steel Tunnels Subjected to External Explosion

2020 ◽  
Vol 10 (18) ◽  
pp. 6166 ◽  
Author(s):  
Cheng-Wei Hung ◽  
Hsin-hung Lai ◽  
Bor-Cherng Shen ◽  
Pin-Wen Wu ◽  
Tai-An Chen
Keyword(s):  
Finite Element ◽  
Numerical Results ◽  
Experimental Results ◽  
Response Model ◽  
Finite Element Code ◽  
Scaled Distance ◽  
Development And Validation

This study employed C4 explosives to evaluate the overpressure response in steel tunnels subjected to external explosions. The explosive scaled distance of the C4 charge from 2.15 to 3.26 m/kg1/3 was evaluated by experiments and the hydrodynamic finite element code LS-DYNA. The numerical results are in agreement with the experimental results. A simple way to estimate the overpressure in steel tunnels was proposed in this paper. The proposed methodology is both useful and efficient and can be further developed for designing protection for military structures and other facilities against explosion.

ON THE PROTECTION CAPABILITY OF THE FLYING PLATE AGAINST TO LONG-ROD PENETRATORS

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1285-1290
Author(s):  
STANISLAV ROLC ◽  
JAROSLAV BUCHAR ◽  
ZBYNEK AKSTEIN
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Numerical Results ◽  
Finite Element Code ◽  
Plate Material ◽  
3D Finite Element ◽  
Plate Velocity ◽  
Long Rod ◽  
Protection Capability

The interaction of the flying plate with the Long-rod penetrator has been studied both experimentally and numerically using the LS DYNA 3D finite element code. The influence of the plate velocity and plate material on this interaction has been investigated in details. Numerical results show that there was a relatively large damage of the projectiles. The extent of this damage well agree with our experimental foundings. The numerical simulation of the damaged projectiles with some targets has been also performed

Two-Dimensional Finite Element Analysis of Laboratory Seawall Model

2014 ◽  
Vol 580-583 ◽  
pp. 2134-2140
Author(s):  
Jian Zhang ◽  
Jian Feng Zhai ◽  
Xian Mei Wang ◽  
Jie Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Numerical Results ◽  
Experimental Results ◽  
Base Layer ◽  
Two Dimensional ◽  
Element Analysis ◽  
Cemented Sand ◽  
Dimensional Finite Element

Two-Dimensional finite element analysis was used to investigate the performance of seawall construction over weak subgrade soil using artificial base layer material consisted of cemented sand cushion comprising geosynthetics materials. Two types of base layer materials pure sand and cemented sand comprising husk rich ash and two types of geosynthetics materials geogrid and geotextile were used. Constitutive models were used to represent different materials in numerical analysis. The competence of two-dimensional numerical analysis was compared with experimental results. Numerical results showed a superior harmony with the experimental results. Finite element analysis model proved to be a great tool to determine the parameters that are difficult to measure in laboratory experiments. In addition, finite element analysis has the benefit of cost and time saving when compared to experimental investigation work. Numerical results showed strain induced in geosynthetics eliminated beyond a distance approximately equal six times of footing width.

scholarly journals Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

2016 ◽  
Vol 61 (2) ◽  
pp. 1003-1008 ◽  
Author(s):  
A. Dziubińska ◽  
A. Gontarz ◽  
K. Dziedzic
Keyword(s):  
Qualitative Research ◽  
Finite Element ◽  
Magnesium Alloy ◽  
Numerical Results ◽  
Experimental Results ◽  
Az31 Magnesium Alloy ◽  
Forming Process ◽  
Closed Die Forging ◽  
Selection Of ◽  
Good Agreement

AbstractThe paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

Finite Element Mass-Conserving Cavitation Algorithm in Pure Squeeze Motion. Validation/Application to a Connecting- Rod Small End Bearing

1999 ◽  
Vol 122 (1) ◽  
pp. 162-169 ◽  
Author(s):  
Virgil Optasanu ◽  
Dominique Bonneau
Keyword(s):  
Finite Element ◽  
Analytical Approach ◽  
Numerical Results ◽  
Oscillatory Motion ◽  
Finite Element Code ◽  
Connecting Rod ◽  
Ehd Lubrication ◽  
Boundary Position

A simple analytical approach using conditions of conservation of the mass is proposed for the 1-D “negative squeeze” lubrication problem in order to calculate the cavitation boundary position during oscillatory motion of two plates. The same geometrical case is analyzed using Bonneau’s finite element code. Good agreements between analytical and numerical results support validation of Bonneau’s algorithm. As an example of application of this algorithm to squeeze motion case, the EHD lubrication of an elastic connecting-rod small end bearing is analyzed. Influences of the shaft elasticity and lubricant piezoviscosity are presented. [S0742-4787(00)02101-9]

Crack Propagation Modeling and Crack Arrestor Design for X120

2006 ◽  
Author(s):  
Andrea Fonzo ◽  
Andrea Meleddu ◽  
Massimo Di Biagio ◽  
Gianluca Mannucci ◽  
Giuseppe Demofonti ◽  
...  
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Wall Thickness ◽  
Full Scale ◽  
Operating Conditions ◽  
Experimental Results ◽  
Finite Element Code ◽  
Pipeline Steels ◽  
Propagation Modeling

The new, higher grade pipeline steels provide an opportunity to reduce pipeline costs by enabling a shift to higher pressure at reasonable wall thickness. However, these higher operating stresses place greater demands on the pipeline, particularly when a running fracture is considered. Several studies have shown that intrinsic arrest cannot be counted on for these grades under all operating conditions. In such cases, crack arrestors will be needed. This paper presents results obtained using CSM’s proprietary PICPRO® finite element code to predict the performance of crack arresters on X120 pipes, and shows that the predictions agree well with full-scale experimental results obtained in arrestor trials.

scholarly journals Verification of FEM modelling of composite materials based on the results of static strength test

Mechanik ◽  
2019 ◽  
Vol 92 (2) ◽  
pp. 131-139
Author(s):  
Katarzyna Gojny
Keyword(s):  
Finite Element ◽  
Composite Materials ◽  
Composite Structure ◽  
Static Strength ◽  
Strength Test ◽  
Numerical Results ◽  
Experimental Results ◽  
Design Stage ◽  
Fem Modeling ◽  
Fem Modelling

The article presents the verification of FEM modelling of composite materials based on the results of static strength test. The aim of the work was to examine whether the applied modelling of composite materials is correct and verify it with finite element method (FEM). The composite structure of the PW-6U glider was used as a model. In the program the numerical model (geometry and finite element mesh) of the glider’s wing was created. The wing is made of glass fabrics and a spar with flanges with a glass roving. The composite structure of the wing, including composition, layout and thickness of laminate layers, fiber arrangement was exactly modelled in the program and then subjected to loads. Having the measurements from the static strength tests of the glider, the numerical results were compared with the experimental results. Thanks to the applied modelling, the obtained numerical results were satisfactory and very close to the experimental results from the structural static tests of the glider. Therefore, it can be concluded that the conducted verification of FEM modelling of composite materials is correct. Nowadays application of composite materials is increasingly expanding. Therefore, the modelling of composites becomes a significant issue. FEM modeling allows verification of the structure. At the stage of modelling modifications can be implemented and thus time and costs associated with subsequent changes in the production process may be saved. This is a very good solution which already at the design stage of the structure allows examination of its strength.

The Effect of Graded Strength on Damage Propagation in Continuously Nonhomogeneous Materials

2003 ◽  
Vol 125 (4) ◽  
pp. 412-417 ◽  
Author(s):  
Priya Thamburaj ◽  
Michael H. Santare ◽  
George A. Gazonas
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Damage Model ◽  
Numerical Results ◽  
Finite Element Code ◽  
Different Boundary Conditions ◽  
One Dimensional ◽  
Damage Propagation ◽  
Dynamic Finite Element ◽  
Nonhomogeneous Materials

A damage model developed by Johnson and Holmquist is implemented into a dynamic finite element code. This is then used to study the effect of grading of the phenomenological damage parameters on the propagation of damage through the material. The numerical results for two one-dimensional example problems with different boundary conditions are presented, wherein the effect of a gradient in the intact strength of the material on damage propagation is studied. The results show that introducing different strength gradients can alter the location of the site of maximum damage. This may have important implications in the design of impact resistant materials and structures.

scholarly journals Numerical and Experimental Investigations on a Three-Dimensional Rod-Plate Impact

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Jianyao Wang ◽  
Zhuyong Liu ◽  
Jiazhen Hong
Keyword(s):  
Finite Element ◽  
Rigid Motion ◽  
Mesh Size ◽  
Numerical Approach ◽  
Numerical Results ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Element Mesh ◽  
Simulation Accuracy ◽  
Oblique Impacts

There are a few numerical simulation methods available for impact problems. However, most numerical results are not validated experimentally. The goal of this paper is to examine how well the simulation results correspond to the physical reality. In this work, normal and oblique impacts of a hemispherical-tip rod on a square plate are investigated both numerically and experimentally. In the numerical approach, finite element method is used to discretize the contact bodies to describe the deformation precisely combined with the floating reference frame method to describe the rigid motion. In the experimental study, strain gauges and Laser Doppler Vibrometers are employed to measure the high-frequency impact responses. Detailed comparative studies between numerical and experimental results are performed. In the case of normal impact, great attention is given to investigate the influence of finite element mesh size on the simulation accuracy and a “Prediction-Refinement” discretization strategy is proposed for obtaining a mesh which is optimal for impact dynamics. In the case of oblique impact, the influence of Coulomb’s friction coefficient is investigated additionally. It shows that the numerical results are in good agreement with the experimental results for both normal and oblique impacts.

Simulation on Ceramic Composite Armors against Multi-Hit of APPs

2011 ◽  
Vol 105-107 ◽  
pp. 1648-1652 ◽  
Author(s):  
Xiao Peng Kong ◽  
Zhi Gang Jiang ◽  
Fei Liu
Keyword(s):  
Finite Element ◽  
Ceramic Composite ◽  
Laminated Composite ◽  
Material Model ◽  
Numerical Results ◽  
Finite Element Code ◽  
Ceramic Tiles ◽  
Contact Algorithm

The multi-hit of armor piercing projectiles (APPs) is one of the main treats to lightweight vehicles. Based on published ballistic experiments of Al2O3/Al2024 laminated composite armors against 7.62mm APP, the debonding of ceramic tiles was successfully simulated by setting reasonable material model and contact algorithm. A method named Geometric Intervals Method (GIM) was developed for simulation of multi-hit and its feasibility and rationality were investigated with the finite element code LS-SYNA. The numerical results shows that GIM has taken into account the effects of target damage caused by former APP impact on the target responds to later APP penetration. GIM can be used to simulate composite amours against multi-hit.

Flow Past a Circular Cylinder: A Comparison Between Commercial Finite Volume and Finite Element Codes

2020 ◽  
Vol 12 (6) ◽  
pp. 815-824
Author(s):  
Guilherme L. F. Vasconcellos ◽  
Alex de Oliveira ◽  
Matheus D. Queiroz ◽  
Jánes Landre Júnior ◽  
Cristiana B. Maia
Keyword(s):  
Finite Element ◽  
Circular Cylinder ◽  
Finite Volume ◽  
Computing Time ◽  
Pressure Coefficient ◽  
Skin Friction Coefficient ◽  
Numerical Results ◽  
Experimental Results ◽  
Fem Method ◽  
Volume Method

This study compares the numerical analyzes of two commercial computational fluid dynamics (CFD) software programs: Ansys® CFX 14.5, based on the finite volume method (FVM); and Altair® AcuSolve 13.0, based on the finite element method (FEM). For this purpose, the flow around a circular cylinder inserted into the test section of a low speed wind tunnel was simulated. The same turbulence model, κ–ω SST (shear stress transport), was used in both software, and the numerical results were compared with experimental results. Results of velocity, pressure, static pressure coefficient and skin friction coefficient are presented. A mesh test was carried out to evaluate the mesh convergence and the numerical uncertainties, which indicated greater uncertainties and sensitivity of FVM to the mesh quality. The average computing time for the FEM method was ten times greater than for FVM. Numerical results of both codes showed a good agreement with experimental results and with the literature.

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