Three-dimensional FE model for fiber interaction effects during microbuckling in composites with isotropic and anisotropic fibers

2007 ◽  
Vol 24 (12) ◽  
pp. 2206-2215 ◽  
Author(s):  
Y. Lapusta ◽  
J. Harich ◽  
W. Wagner
Keyword(s):  
Three Dimensional ◽  
Interaction Effects ◽  
Fe Model ◽  
Fiber Interaction

scholarly journals Numerical Analysis of the Perforated Steel Sheets Under Uni-Axial Tensile Force

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 632 ◽  
Author(s):  
Ahmed M. Sayed
Keyword(s):  
Load Capacity ◽  
Tensile Force ◽  
Three Dimensional ◽  
Tensile Load ◽  
Experimental Tests ◽  
Strain Engineering ◽  
Uniaxial Tensile ◽  
Fe Model ◽  
Stress Strain ◽  
Steel Sheets

The perforated steel sheets have many uses, so they should be studied under the influence of the uniaxial tensile load. The presence of these holes in the steel sheets certainly affects the mechanical properties. This paper aims at studying the behavior of the stress-strain engineering relationships of the perforated steel sheets. To achieve this, the three-dimensional finite element (FE) model is mainly designed to investigate the effect of this condition. Experimental tests were carried out on solid specimens to be used in the test of model accuracy of the FE simulation. Simulation testing shows that the FE modeling revealed the ability to calculate the stress-strain engineering relationships of perforated steel sheets. It can be concluded that the effect of a perforated rhombus shape is greater than the others, and perforated square shape has no effect on the stress-strain engineering relationships. The efficiency of the perforated staggered or linearly distribution shapes with the actual net area on the applied loads has the opposite effect, as it reduces the load capacity for all types of perforated shapes. Despite the decrease in load capacity, it improves the properties of the steel sheets.

Finite Element Study of the Cutting Mechanics of the Three Dimensional Rock Turning Process

2015 ◽  
Author(s):  
Demeng Che ◽  
Jacob Smith ◽  
Kornel F. Ehmann
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Polycrystalline Diamond ◽  
Close Correlation ◽  
Experimental Results ◽  
Failure Behavior ◽  
Fe Model ◽  
Gas Drilling ◽  
Cutting Mechanics

The unceasing improvements of polycrystalline diamond compact (PDC) cutters have pushed the limits of tool life and cutting efficiency in the oil and gas drilling industry. However, the still limited understanding of the cutting mechanics involved in rock cutting/drilling processes leads to unsatisfactory performance in the drilling of hard/abrasive rock formations. The Finite Element Method (FEM) holds the promise to advance the in-depth understanding of the interactions between rock and cutters. This paper presents a finite element (FE) model of three-dimensional face turning of rock representing one of the most frequent testing methods in the PDC cutter industry. The pressure-dependent Drucker-Prager plastic model with a plastic damage law was utilized to describe the elastic-plastic failure behavior of rock. A newly developed face turning testbed was introduced and utilized to provide experimental results for the calibration and validation of the formulated FE model. Force responses were compared between simulations and experiments. The relationship between process parameters and force responses and the mechanics of the process were discussed and a close correlation between numerical and experimental results was shown.

scholarly journals Modelling human skull growth: a validated computational model

2017 ◽  
Vol 14 (130) ◽  
pp. 20170202 ◽  
Author(s):  
Joseph Libby ◽  
Arsalan Marghoub ◽  
David Johnson ◽  
Roman H. Khonsari ◽  
Michael J. Fagan ◽  
...  
Keyword(s):  
Computational Model ◽  
Three Dimensional ◽  
Basic Knowledge ◽  
Fe Model ◽  
Adult Size ◽  
Fe Method ◽  
Percentage Difference ◽  
Skull Growth

During the first year of life, the brain grows rapidly and the neurocranium increases to about 65% of its adult size. Our understanding of the relationship between the biomechanical forces, especially from the growing brain, the craniofacial soft tissue structures and the individual bone plates of the skull vault is still limited. This basic knowledge could help in the future planning of craniofacial surgical operations. The aim of this study was to develop a validated computational model of skull growth, based on the finite-element (FE) method, to help understand the biomechanics of skull growth. To do this, a two-step validation study was carried out. First, an in vitro physical three-dimensional printed model and an in silico FE model were created from the same micro-CT scan of an infant skull and loaded with forces from the growing brain from zero to two months of age. The results from the in vitro model validated the FE model before it was further developed to expand from 0 to 12 months of age. This second FE model was compared directly with in vivo clinical CT scans of infants without craniofacial conditions ( n = 56). The various models were compared in terms of predicted skull width, length and circumference, while the overall shape was quantified using three-dimensional distance plots. Statistical analysis yielded no significant differences between the male skull models. All size measurements from the FE model versus the in vitro physical model were within 5%, with one exception showing a 7.6% difference. The FE model and in vivo data also correlated well, with the largest percentage difference in size being 8.3%. Overall, the FE model results matched well with both the in vitro and in vivo data. With further development and model refinement, this modelling method could be used to assist in preoperative planning of craniofacial surgery procedures and could help to reduce reoperation rates.

Streckziehen keramischer Grünfolien*/Stretch drawing of ceramic green tapes - Investigation of the factors influencing to the stretch drawing capacity of ceramic green tapes

2016 ◽  
Vol 106 (11-12) ◽  
pp. 847-850
Author(s):  
Q. Spiller ◽  
M. Baumeister ◽  
J. Prof. Fleischer
Keyword(s):  
Statistical Methods ◽  
Three Dimensional ◽  
Interaction Effects ◽  
Powder Technology ◽  
Factors Influencing ◽  
Statistische Methoden ◽  
Main Effects

Im Bereich der Pulvertechnologie stellt das Streckziehen keramischer Grünfolien eine wirtschaftliche Möglichkeit dar, dreidimensionale Halbzeuge herzustellen. Im Rahmen des AiF-Projekts „Inka“ werden die Einflüsse der Prozess- und Geometrieparameter auf die Streckziehfähigkeit von keramischen Grünfolien aus dem Werkstoff ZrO2 experimentell untersucht. Dabei kommen statistische Methoden zur Ermittlung der Haupt- und Wechselwirkungseffekte zum Einsatz.   In the field of powder technology stretch drawing is an economic way to produce three-dimensional semi-finished products. In the context of the AIF Project “Inka“ the influences of process and geometry parameters are experimental examined on stretch drawing capacity of ceramic green tapes of material ZrO2. Statistical methods are used to find out main effects and interaction effects.

Management of Complex Loading Histories for Use in Probabilistic Creep-Fatigue Damage Assessments

2018 ◽  
Author(s):  
N. A. Zentuti ◽  
J. D. Booker ◽  
R. A. W. Bradford ◽  
C. E. Truman
Keyword(s):  
Fatigue Damage ◽  
Input Parameter ◽  
Three Dimensional ◽  
Complex Loading ◽  
Fe Model ◽  
Plant Component ◽  
Fatigue Lifetime ◽  
Wide Range ◽  
Stress Components ◽  
Creep Fatigue

An approach is outlined for the treatment of stresses in complex three-dimensional components for the purpose of conducting probabilistic creep-fatigue lifetime assessments. For conventional deterministic assessments, the stress state in a plant component is found using thermal and mechanical (elastic) finite element (FE) models. Key inputs are typically steam temperatures and pressures, with the three principal stress components (PSCs) at the assessment location(s) being the outputs. This paper presents an approach which was developed based on application experience with a tube-plate ligament (TPL) component, for which historical data was available. Though both transient as well as steady-state conditions can have large contributions towards the creep-fatigue damage, this work is mainly concerned with the latter. In a probabilistic assessment, the aim of this approach is to replace time intensive FE runs with a predictive model to approximate stresses at various assessment locations. This is achieved by firstly modelling a wide range of typical loading conditions using FE models to obtain the desire stresses. Based on the results from these FE runs, a probability map is produced and input(s)-output(s) functions are fitted (either using a Response Surface Method or Linear Regression). These models are thereafter used to predict stresses as functions of the input parameter(s) directly. This mitigates running an FE model for every probabilistic trial (of which there typically may be more than 104), an approach which would be computationally prohibitive.

Three-Dimensional Interaction Effects in an Internally Multicracked Pressurized Thick-Walled Cylinder— Part I: Radial Crack Arrays

1996 ◽  
Vol 118 (3) ◽  
pp. 357-363 ◽  
Author(s):  
M. Perl ◽  
C. Levy ◽  
J. Pierola
Keyword(s):  
Radial Crack ◽  
Crack Depth ◽  
Three Dimensional ◽  
Internal Surface ◽  
Interaction Effects ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Dimensional Interaction ◽  
Least Squares Fit ◽  
Wide Range

Under certain conditions, numerous internal surface cracks develop in pressurized thick-walled cylinders, both in the radial and longitudinal directions. For fatigue life assessment of such vessels, the 3-D interaction effects among these cracks on the prevailing stress intensity factors (SIFs) need evaluation. In Part I of this paper, radial crack arrays are considered exclusively. The mode I SIF distribution for a wide range of semi-circular and semi-elliptical cracks are evaluated. The 3-D analysis is performed via the finite element method with the submodeling technique, employing singular elements along the crack front. SIFs are evaluated for arrays of up to n = 180 cracks; for a wide range of crack depth to wall thickness ratios, a/t, from 0.05 to 0.6; and, for various ellipticities of the crack, i.e., the ratio of crack depth to semicrack length, a/c, from 0.2 to 2. Using a least-squares fit, two simple expressions for the most critical (n = 2) SIFs are obtained for sparse and dense crack arrays. The formulas, which are functions of a/t and a/c, are of very good engineering accuracy. The results clearly indicate that the SIFs are considerably affected by the interaction among the cracks in the array as well as the three-dimensionality of the problem. In Part II of this paper, the interaction effects between longitudinal coplanar cracks will be analyzed.

scholarly journals Established Numerical Techniques for the Structural Analysis of a Regional Aircraft Landing Gear

2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
F. Caputo ◽  
A. De Luca ◽  
A. Greco ◽  
A. Marro ◽  
A. Apicella ◽  
...  
Keyword(s):  
Finite Elements ◽  
Numerical Models ◽  
Three Dimensional ◽  
Landing Gear ◽  
Point Of View ◽  
Fe Model ◽  
One Dimensional ◽  
Reaction Forces ◽  
Local Technique ◽  
Stick Model

Usually during the design of landing gear, simplified Finite Element (FE) models, based on one-dimensional finite elements (stick model), are used to investigate the in-service reaction forces involving each subcomponent. After that, the design of such subcomponent is carried out through detailed Global/Local FE analyses where, once at time, each component, modelled with three-dimensional finite elements, is assembled into a one-dimensional finite elements based FE model, representing the whole landing gear under the investigated loading conditions. Moreover, the landing gears are usually investigated also under a kinematic point of view, through the multibody (MB) methods, which allow achieving the reaction forces involving each subcomponent in a very short time. However, simplified stick (FE) and MB models introduce several approximations, providing results far from the real behaviour of the landing gear. Therefore, the first goal of this paper consists of assessing the effectiveness of such approaches against a 3D full-FE model. Three numerical models of the main landing gear of a regional airliner have been developed, according to MB, “stick,” and 3D full-FE methods, respectively. The former has been developed by means of ADAMS® software, the other two by means of NASTRAN® software. Once this assessment phase has been carried out, also the Global/Local technique has verified with regard to the results achieved by the 3D full-FE model. Finally, the dynamic behaviour of the landing gear has been investigated both numerically and experimentally. In particular, Magnaghi Aeronautica S.p.A. Company performed the experimental test, consisting of a drop test according to EASA CS 25 regulations. Concerning the 3D full-FE investigation, the analysis has been simulated by means of Ls-Dyna® software. A good level of accuracy has been achieved by all the developed numerical methods.

The Effect of Trabecular Bone on the Mechanical Response of Human Mandible with Implant

2014 ◽  
Vol 695 ◽  
pp. 588-591
Author(s):  
Khairul Salleh Basaruddin ◽  
Ruslizam Daud
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Trabecular Bone ◽  
Static Analysis ◽  
Load Distribution ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Fe Model ◽  
Micro Computed Tomography ◽  
Bone Specimen

This study aims to investigate the influence of trabecular bone in human mandible bone on the mechanical response under implant load. Three dimensional voxel finite element (FE) model of mandible bone was reconstructed from micro-computed tomography (CT) images that were captured from bone specimen. Two FE models were developed where the first consists of cortical bone, trabecular bone and implants, and trabecular bone part was excluded in the second model. A static analysis was conducted on both models using commercial software Voxelcon. The results suggest that trabecular bone contributed to the strength of human mandible bone and to the effectiveness of load distribution under implant load.

Forced Response Variation of Aerodynamically and Structurally Mistuned Turbo-Machinery Rotors

2006 ◽  
Author(s):  
I. Sladojevic´ ◽  
E. P. Petrov ◽  
M. Imregun ◽  
A. I. Sayma
Keyword(s):  
Three Dimensional ◽  
Forced Response ◽  
Navier Stokes ◽  
Fe Model ◽  
Frequency Shifts ◽  
Aero Engine ◽  
Different Types ◽  
Aerodynamic Parameters ◽  
Reynolds Averaged Navier Stokes ◽  
Response Variation

The paper presents the results of a study looking into changes in the forced response levels of bladed disc assemblies subject to both structural and aerodynamic mistuning. A whole annulus FE model, representative of a civil aero-engine fan with 26 blades was used in the calculations. The forced response of all blades of 1000 random mistuned patterns was calculated. The aerodynamic parameters, frequency shifts and damping, were calculated using a three-dimensional Reynolds-averaged Navier-Stokes aero-elasticity code. They were randomly varied for each mistuning pattern, with the assumption that the system would remain stable, i.e. flutter would not occur due to aerodynamic mistuning. The results show the variation of the forced response with different types of mistuning, with structural mistuning only, with aerodynamic mistuning only and with both structural and aerodynamic mistuning.

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