scholarly journals Technical Brief: Finite Element Modeling of Tight Elastic Knots

2020 ◽  
pp. 1-7
Author(s):  
Changyeob Baek ◽  
Paul Johanns ◽  
Tomohiko G. Sano ◽  
Paul Grandgeorge ◽  
Pedro M. Reis

Abstract We present a methodology to simulate the mechanics of knots in elastic rods using geometrically nonlinear, full three-dimensional (3D) finite element analysis. We focus on the mechanical behavior of knots in tight configurations, for which the full 3D deformation must be taken into account. To set up the topology of our knotted structures, we apply a sequence of prescribed displacement steps to the centerline of an initially straight rod that is meshed with 3D solid elements. Self-contact is enforced with a normal penalty force combined with Coulomb friction. As test cases, we investigate both overhand and figure-of-eight knots. Our simulations are validated with precision model experiments, combining rod fabrication and X-ray tomography. Even if the focus is given to the methods, our results reveal that 3D deformation of tight elastic knots is central to their mechanical response. These findings contrast to a previous analysis of loose knots, for which 1D centerline-based rod theories sufficed for a predictive understanding. Our method serves as a robust framework to access complex mechanical behavior of tightly knotted structures that are not readily available through experiments nor existing reduced-order theories.

1970 ◽  
Vol 3 ◽  
pp. 17-18
Author(s):  
Raquel Simón-Allué ◽  
Assad Oberai ◽  
Begoña Calvo

In this work we develop a methodology to characterize in vivo the passive mechanical behavior of abdominal muscle, using for that finite element simulations combined with inverse analysis and optimization algorithms. The knowledge of the mechanical response of the muscle is needed to determine the features of the mesh in cases of hernia surgery.


Author(s):  
Carlo Boursier Niutta ◽  
Raffaele Ciardiello ◽  
Giovanni Belingardi ◽  
Alessandro Scattina

In this work, the mechanical properties of two different adhesives compositions have been investigated both experimentally and numerically. The studied thermoplastic adhesives are Hot-Melt Adhesive (HMA). In particular, a pristine and a nanomodified adhesive with 10% in weight of iron oxide have been considered. The adhesives have been subjected to a series of single lap joint (SLJ) tests using adherends made of polypropylene copolymer. As it is well-known, the structural-mechanical behavior of adhesive joints is mostly influenced by the bonding process: thickness of adhesive as well as its application procedures and the surface preparation of adherends are among the most influencing factors. In addition, the mechanical behavior of SLJ test is particularly influenced by the correct alignment of adherends and applied load. These aspects have been investigated, analyzing the experimental results. Moreover, the experimental results have been used to develop a numerical model of the two adhesives. The numerical analysis has been carried out using the commercial software LS-DYNA. Transient nonlinear finite element analysis has been performed to simulate the mechanical behavior of the thermoplastic adhesives. In particular, the cohesive formulations of the elements have been taken into consideration after a careful literature review. In order to set-up and to validate the mechanical properties of the adhesives, the experimental SLJ tests have been simulated. The developed finite element models enable to investigate more complex joint structures where these types of adhesives are used, such as plastic piping systems and automotive applications. Further, the numerical models allow to investigate with higher accuracy and lower time different aspects such as manufacturing and non-linear effects.


2011 ◽  
Vol 90-93 ◽  
pp. 1212-1215 ◽  
Author(s):  
Yan Zeng ◽  
Zhi Yong Wang

In this paper dynamic behavior of the Ying Zhou main bridge in Luoyang is studied .The finite element analysis software ANSYS is adopted to set up three-dimensional finite element model of a CFT arch bridge of the main bridge .The natural periods and modes of the CFT arch bridge are calculated by using the subspace iteration method. Meanwhile its modal characteristics are analyzed. Some useful conclusions are got by the calculation and analysis of the bridge for the engineering construction.


2012 ◽  
Vol 472-475 ◽  
pp. 2024-2028
Author(s):  
Sheng Guo ◽  
Wei Ping Huang ◽  
Nian Qing Guo

According to the main parameters of the jaw crusher PC5282, structure of the back frame was designed, and three-dimensional model of the back frame was also set up. Finite element analysis of the back frame under static load was done in COSMOSWORKS. The distribution laws of stress, displacement and deformation were revealed. Optimization design was also finished, and the weight of the back frame was reduced.


2016 ◽  
Vol 680 ◽  
pp. 72-75
Author(s):  
Yan Min ◽  
Zeng Chen Cao ◽  
Shuang Li

Based on GB/T 5137.1-2002 experiment specification, the finite element model of head-form impacting laminated glass for automotive windscreens is set up in this paper. According to Finite Element Analysis results of laminated glass with different structure and further analyzing impact property and mechanism of laminated glass , the influence rule of the structure of the laminated glass on the mechanical behavior is discussed. (H)


2014 ◽  
Vol 597 ◽  
pp. 531-534
Author(s):  
Zhi Dong Huang ◽  
Yun Pu Du ◽  
Bao Quan Liu ◽  
Guang Yang ◽  
Yu Feng Liu ◽  
...  

Based on Solidworks software, the three-dimensional model of two wheels scooter is set up. The finite element model of two wheels scooter is generated. Finite element analysis of driving system on two wheels scooter is investigated. The stress and strain of driving system is investigated. The stress diagram and the strain diagram are obtained. The method and the result can be used as a reference of innovative design of two wheels scooter.


Prosthesis ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 173-180
Author(s):  
Nathália de Carvalho Ramos ◽  
Gabriela Freitas Ramos ◽  
Marcela Moreira Penteado ◽  
Renata Marques de Melo ◽  
Alexandre Luiz Souto Borges ◽  
...  

Different all-ceramic crown designs are available to perform indirect restoration; however, the mechanical response of each model should still be elucidated. The study aims to evaluate the stress distribution in three different zirconia crown designs using finite element analysis. Different three-dimensional molar crowns were simulated: conventional bilayer zirconia covered with porcelain, a monolithic full-contour zirconia crown, and the cutback modified zirconia crown with porcelain veneered buccal face. The models were imported to the computer-aided engineering (CAE) software. Tetrahedral elements were used to form the mesh and the mechanical properties were assumed as isotropic, linear and homogeneous materials. The contacts were considered ideal. For the static structural mechanical analysis, 100 N occlusal load was applied and the bone tissue was fixed. Maximum principal stress showed that the stress pattern was different for the three crown designs, and the traditional bilayer model showed higher stress magnitude comparing to the other models. However, grayscale stress maps showed homogeneous stress distribution for all models. The all-ceramic crown designs affect the stress distribution, and the cutback porcelain-veneered zirconia crown can be a viable alternative to adequate function and esthetic when the monolithic zirconia crown cannot be indicated.


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.


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