scholarly journals A Computational Approach to Model Interfacial Effects on the Mechanical Behavior of Knitted Textiles

2018 ◽  
Vol 85 (4) ◽  
Author(s):  
Dani Liu ◽  
Bahareh Shakibajahromi ◽  
Genevieve Dion ◽  
David Breen ◽  
Antonios Kontsos

The mechanical behavior of knitted textiles is simulated using finite element analysis (FEA). Given the strong coupling between geometrical and physical aspects that affect the behavior of this type of engineering materials, there are several challenges associated with the development of computational tools capable of enabling physics-based predictions, while keeping the associated computational cost appropriate for use within design optimization processes. In this context, this paper investigates the relative contribution of a number of computational factors to both local and global mechanical behavior of knitted textiles. Specifically, different yarn-to-yarn interaction definitions in three-dimensional (3D) finite element models are compared to explore their relative influence on kinematic features of knitted textiles' mechanical behavior. The relative motion between yarns identified by direct numerical simulations (DNS) is then used to construct reduced order models (ROMs), which are shown to be computationally more efficient and providing comparable predictions of the mechanical performance of knitted textiles that include interfacial effects between yarns.

Author(s):  
Nic Debusschere ◽  
Matthieu De Beule ◽  
Peter Dubruel ◽  
Patrick Segers ◽  
Benedict Verhegghe

Biodegradable stents, which temporarily support a stenotic blood vessel and afterwards fully disappear, have recently gained a lot of interest. They avoid long-term complications associated with conventional stents such as late stent thrombosis and in-stent restenosis. Moreover, degradable stents allow for a restoration of vasomotion and vessel growth which makes them particularly suitable for pediatric applications [1]. Finite element simulations have proven to be an efficient and cost-effective tool to investigate and optimize the mechanical performance of minimal invasive devices such as stents [2]. Biodegradable stents have however created new challenges in their design and optimization via finite element analysis because of their complex time-varying material behavior. To correctly simulate the mechanical behavior of biodegradable stents, a model should be developed that incorporates the effect of degradation upon all material characteristics. By combining existing constitutive material models based on continuum damage theory we were able to create such a virtual environment in which the transitional mechanical behavior of biodegradable stents can be investigated.


2014 ◽  
Vol 651-653 ◽  
pp. 1197-1200
Author(s):  
Kai Wen Li ◽  
Zhi Yang Li ◽  
Yun Zou

Finite element analysis could be used as a supplementary means to investigate mechanical behavior. ABAQUS software is conducted to analyze steel reinforced concrete (SRC) columns. Firstly, in order to validate the rationality of the analytical model, finite element models of test specimens are established to simulate the test process. By comparing the analytical results with experimental ones, it is found that the results from finite element analysis coincide well with that from test. So ABAQUS software could be used as a supplementary means to simulate SRC column mechanical behavior . Further the ductility and ultimate capacity of SRC columns are studied with the changes of steel bone ratio and the axial compressive ratio.


2013 ◽  
Vol 461 ◽  
pp. 993-1001
Author(s):  
Wen Wen Deng ◽  
Fang Wang ◽  
Ferdinand M. Machibya ◽  
Shang Gao ◽  
Xiao Long Wang ◽  
...  

Introduction: An en-masse retraction with mini implant (MI) anchorage may be associated with unwanted intrusion/extrusion and uncontrolled tipping of anterior teeth. An optimum combination of MIs and hooks heights is required for proper treatment results. Materials and Methods: Maxillary finite element models were constructed from a cone beam CT scan of a patient’s orofacial region. The initial tooth displacement at 200g force with 0.019 × 0.025-in stainless steel working archwires engaged in 0.022 brackets slot was assessed. The three-dimensional displacement was examined at various MI and AAH heights. Results: The lower MI position caused extrusion of the central incisors, but the teeth were intruded at higher (6- and 8-mm) MI heights. While the shorter (2- and 4-mm) hooks extruded the central incisors, the higher (6- and 8-mm) intruded the teeth. The higher MI and hooks reduced the palatal tipping of central incisors. The distobucal cusp of the first molar was intruded, while the mesiobucal cusp was extruded in all models: Nonetheless, the shorter hooks and low MI had small molar tipping effects. Conclusions: The higher MIs caused intrusion and less palatal tipping of the central incisors crowns. The increase in hook height resulted into extrusion and reduction in palatal tipping of the central incisors crowns.


Tribologia ◽  
2016 ◽  
Vol 266 (2) ◽  
pp. 9-24 ◽  
Author(s):  
Oday I. ABDULLAH ◽  
Laith Abed SABRI ◽  
Wassan S. Abd Al-SAHB

Most of the failures in the sliding systems occur due to the high thermal stresses, which generated at the interface between the contacting surfaces due to sliding between parts, such as friction clutches and brakes. In this paper, the thermal behaviour of a single-disc clutch is investigated. The surface temperatures of the friction clutch disc will be increased during repeated engagements, in some cases, will lead to premature failure of the clutch disc. In order to avoid this kind of failure, it the surface temperature should be calculated with high accuracy to know the maximum working temperature of the friction system. In this work, the temperature distributions are computed during four repeated engagements at regular intervals (5 s) for the same energy dissipation. Three-dimensional finite element models are used to simulate the typical friction clutch disc.


2019 ◽  
Vol 16 (161) ◽  
pp. 20190674 ◽  
Author(s):  
Nuria Melisa Morales-García ◽  
Thomas D. Burgess ◽  
Jennifer J. Hill ◽  
Pamela G. Gill ◽  
Emily J. Rayfield

Finite-element (FE) analysis has been used in palaeobiology to assess the mechanical performance of the jaw. It uses two types of models: tomography-based three-dimensional (3D) models (very accurate, not always accessible) and two-dimensional (2D) models (quick and easy to build, good for broad-scale studies, cannot obtain absolute stress and strain values). Here, we introduce extruded FE models, which provide fairly accurate mechanical performance results, while remaining low-cost, quick and easy to build. These are simplified 3D models built from lateral outlines of a relatively flat jaw and extruded to its average width. There are two types: extruded (flat mediolaterally) and enhanced extruded (accounts for width differences in the ascending ramus). Here, we compare mechanical performance values resulting from four types of FE models (i.e. tomography-based 3D, extruded, enhanced extruded and 2D) in Morganucodon and Kuehneotherium . In terms of absolute values, both types of extruded model perform well in comparison to the tomography-based 3D models, but enhanced extruded models perform better. In terms of overall patterns, all models produce similar results. Extruded FE models constitute a viable alternative to the use of tomography-based 3D models, particularly in relatively flat bones.


Author(s):  
Daniel Sommerville ◽  
Matthew Walter

Two dimensional (2-D) axisymmetric finite element models (FEMs) are often used as a simplification to modeling cylindrical nozzles that intersect a cylindrical pressure vessel. However, an axisymmetric model has the effect of representing the vessel as a spherical shell rather than a cylindrical shell. Previous work has been done to determine 2-D axisymmetric to three dimensional (3-D) stress correction factors (CFs) for the total stress at the nozzle blend radius to account for this inconsistency. The present paper expands on that work to investigate the effects of the 2-D axisymmetric modeling simplification on the through wall stress distribution at the nozzle corner. The through-wall stress distribution is necessary for some fracture mechanics analyses performed for corner cracked nozzles and for using the simplified elastic-plastic analysis given in NB-3228.5. A simplified method is proposed which can be used to obtain a nozzle specific correction factor, rather than a bounding correction factor, that can be applied to 2-D finite element analysis stress results to correct for the inaccuracy introduced by modeling the intersection as an axisymmetric section.


1974 ◽  
Vol 96 (3) ◽  
pp. 200-206 ◽  
Author(s):  
L. W. Kirchhoff

A description is given of a computer graphics program for detecting errors in three-dimensional finite element models and reducing finite element analysis data to a usable form. An efficient hidden line algorithm for mixed sets of polygons and polyhedra is presented together with a general line classification scheme. They are used to produce the variety of plots necessary to detect errors in the model. They also provide an “uncluttered” surface for displaying stress, temperature, and displacement data.


1998 ◽  
Vol 120 (2) ◽  
pp. 126-130 ◽  
Author(s):  
D. C. Stahl ◽  
S. M. Cramer

A procedure is described that predicts the mechanical behavior of a fibrous material by generating and analyzing finite element models of its three-dimensional microstructure. The approach is applicable to a class of materials with microstructures consisting of fibers connected at well-defined points. The procedure allows one to predict the effect of important sources of heterogeneity in these materials. Analyses determine initial elastic properties, failure mode, and strength of the composite; the failure analysis consists of tracking a progression of micro failures. The procedure is validated by comparison of predictions to test results.


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