scholarly journals Stress-Softening and Residual Strain Effects in Suture Materials

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Alex Elías-Zúñiga ◽  
Beatriz Montoya ◽  
Wendy Ortega-Lara ◽  
Eduardo Flores-Villalba ◽  
Ciro A. Rodríguez ◽  
...  
Keyword(s):  
Residual Strain ◽  
Suture Material ◽  
Material Model ◽  
Suture Materials ◽  
Softening Function ◽  
Strain Effects ◽  
Stress Softening ◽  
Constitutive Material Model ◽  
Residual Strains ◽  
Loading And Unloading

This work focuses on the experimental characterization of suture material samples of MonoPlus, Monosyn, polyglycolic acid, polydioxanone 2–0, polydioxanone 4–0, poly(glycolide-co-epsilon-caprolactone), nylon, and polypropylene when subjected to cyclic loading and unloading conditions. It is found that all tested suture materials exhibit stress-softening and residual strain effects related to the microstructural material damage upon deformation from the natural, undistorted state of the virgin suture material. To predict experimental observations, a new constitutive material model that takes into account stress-softening and residual strain effects is developed. The basis of this model is the inclusion of a phenomenological nonmonotonous softening function that depends on the strain intensity between loading and unloading cycles. The theory is illustrated by modifying the non-Gaussian average-stretch, full-network model to capture stress-softening and residual strains by using pseudoelasticity concepts. It is shown that results obtained from theoretical simulations compare well with suture material experimental data.

scholarly journals A Nonmonotonous Damage Model to Characterize Mullins and Residual Strain Effects of Rubber Strings Subjected to Transverse Vibrations

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Alex Elías-Zúñiga ◽  
Karen Baylón ◽  
Oscar Martínez-Romero ◽  
Ciro A. Rodríguez ◽  
Héctor R. Siller
Keyword(s):  
Experimental Data ◽  
Residual Strain ◽  
Damage Model ◽  
Material Model ◽  
Softening Function ◽  
Strain Effects ◽  
Transverse Vibrations ◽  
Theoretical Predictions ◽  
Loading And Unloading ◽  
Vibration Tests

This work focuses on the formulation of a constitutive equation to predict Mullins and residual strain effects of buna-N, silicone, and neoprene rubber strings subjected to small transverse vibrations. The nonmonotone behavior exhibited by experimental data is captured by the proposed material model through the inclusion of a phenomenological non-monotonous softening function that depends on the strain intensity between loading and unloading cycles. It is shown that theoretical predictions compare well with uniaxial experimental data collected from transverse vibration tests.

scholarly journals Transversely isotropic cyclic stress-softening model for the Mullins effect

2012 ◽  
Vol 468 (2148) ◽  
pp. 4041-4057 ◽  
Author(s):  
Stephen R. Rickaby ◽  
Nigel H. Scott
Keyword(s):  
Residual Strain ◽  
Transversely Isotropic ◽  
Cyclic Stress ◽  
Elastic Response ◽  
Chain Model ◽  
Mullins Effect ◽  
Softening Function ◽  
Stress Softening ◽  
Cyclic Loading And Unloading ◽  
Isotropic Hyperelastic Material

This paper models stress softening during cyclic loading and unloading of an elastomer. The paper begins by remodelling the primary loading curve to include a softening function and goes on to derive nonlinear transversely isotropic constitutive equations for the elastic response, stress relaxation, residual strain and creep of residual strain. These ideas are combined with a transversely isotropic version of the Arruda–Boyce eight-chain model to develop a constitutive relation that is capable of accurately representing the Mullins effect during cyclic stress softening for a transversely isotropic, hyperelastic material, in particular, a carbon-filled rubber vulcanizate.

scholarly journals Investigation of the Effect of Carbonyl Iron Micro-Particles on the Mechanical and Rheological Properties of Isotropic and Anisotropic MREs: Constitutive Magneto-Mechanical Material Model

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1705 ◽  
Author(s):  
Cintya Soria-Hernández ◽  
Luis Palacios-Pineda ◽  
Alex Elías-Zúñiga ◽  
Imperio Perales-Martínez ◽  
Oscar Martínez-Romero
Keyword(s):  
Magnetic Flux ◽  
Rheological Properties ◽  
Flux Density ◽  
Carbonyl Iron ◽  
Material Model ◽  
Magnetic Flux Density ◽  
Stress Softening ◽  
Permanent Set ◽  
Micro Particles ◽  
Constitutive Material Model

This article focuses on evaluating the influence that the addition of carbonyl iron micro-particles (CIPs) and its alignment have on the mechanical and rheological properties for magnetorheological elastomers (MREs) fabricated using polydimethylsiloxane (PDMS) elastomer, and 24 wt % of silicone oil (SO). A solenoid device was designed and built to fabricate the corresponding composite magnetorheological material and to perform uniaxial cyclic tests under uniform magnetic flux density. Furthermore, a constitutive material model that considers both elastic and magnetic effects was introduced to predict stress-softening and permanent set effects experienced by the MRE samples during cyclic loading tests. Moreover, experimental characterizations via Fourier transform infrared (FTIR), X-ray diffraction (XRD), tensile mechanical testing, and rheological tests were performed on the produced MRE samples in order to assess mechanical and rheological material properties such as mechanical strength, material stiffness, Mullins and permanent set effects, damping ratio, stiffness magnetorheological effect (SMR), and relative magnetorheological storage and loss moduli effects. Experimental results and theoretical predictions confirmed that for a CIPs concentration of 70 wt %, the material samples exhibit the highest shear modulus, stress-softening effects, and engineering stress values when the samples are subject to a maximum stretch value of 1.64 and a uniform magnetic flux density of 52.2 mT.

Noninvasive In Vivo Determination of Residual Strains and Stresses

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Samir Donmazov ◽  
Senol Piskin ◽  
Kerem Pekkan
Keyword(s):  
Experimental Data ◽  
Residual Stress ◽  
Residual Strain ◽  
Analytical Approach ◽  
Measurement Techniques ◽  
Data Sets ◽  
Residual Strains ◽  
Loading And Unloading

Vascular growth and remodeling during embryonic development are associated with blood flow and pressure induced stress distribution, in which residual strains and stresses play a central role. Residual strains are typically measured by performing in vitro tests on the excised vascular tissue. In this paper, we investigated the possibility of estimating residual strains and stresses using physiological pressure–radius data obtained through in vivo noninvasive measurement techniques, such as optical coherence tomography or ultrasound modalities. This analytical approach first tested with in vitro results using experimental data sets for three different arteries such as rabbit carotid artery, rabbit thoracic artery, and human carotid artery based on Fung’s pseudostrain energy function and Delfino’s exponential strain energy function (SEF). We also examined residual strains and stresses in the human swine iliac artery using the in vivo experimental ultrasound data sets corresponding to the systolic-to-diastolic region only. This allowed computation of the in vivo residual stress information for loading and unloading states separately. Residual strain parameters as well as the material parameters were successfully computed with high accuracy, where the relative errors are introduced in the range of 0–7.5%. Corresponding residual stress distributions demonstrated global errors all in acceptable ranges. A slight discrepancy was observed in the computed reduced axial force. Results of computations performed based on in vivo experimental data obtained from loading and unloading states of the artery exhibited alterations in material properties and residual strain parameters as well. Emerging noninvasive measurement techniques combined with the present analytical approach can be used to estimate residual strains and stresses in vascular tissues as a precursor for growth estimates. This approach is also validated with a finite element model of a general two-layered artery, where the material remodeling states and residual strain generation are investigated.

scholarly journals On the Rule of Mixtures for Predicting Stress-Softening and Residual Strain Effects in Biological Tissues and Biocompatible Materials

Materials ◽  
2014 ◽  
Vol 7 (1) ◽  
pp. 441-456 ◽  
Author(s):  
Alex Elías-Zúñiga ◽  
Karen Baylón ◽  
Inés Ferrer ◽  
Lídia Serenó ◽  
Maria García-Romeu ◽  
...  
Keyword(s):  
Residual Strain ◽  
Biological Tissues ◽  
Biocompatible Materials ◽  
Strain Effects ◽  
Stress Softening ◽  
Rule Of Mixtures

Absorbable suture material in carotid surgery

VASA ◽  
2015 ◽  
Vol 44 (6) ◽  
pp. 451-457 ◽  
Author(s):  
Vincenzo Gasbarro ◽  
Luca Traina ◽  
Francesco Mascoli ◽  
Vincenzo Coscia ◽  
Gianluca Buffone ◽  
...  
Keyword(s):  
Suture Material ◽  
Absorbable Suture ◽  
Paediatric Surgery ◽  
Carotid Surgery ◽  
Suture Materials ◽  
Absorbable Suture Material ◽  
Absorbable Sutures ◽  
Group A ◽  
Group B

Abstract. Background: Absorbable sutures are not generally accepted by most vascular surgeons for the fear of breakage of the suture line and the risk of aneurysmal formation, except in cases of paediatric surgery or in case of infections. Aim of this study is to provide evidence of safety and efficacy of the use of absorbable suture materials in carotid surgery. Patients and methods: In an 11 year period, 1126 patients (659 male [58.5 %], 467 female [41.5 %], median age 72) underwent carotid endarterectomy for carotid stenosis by either conventional with primary closure (cCEA) or eversion (eCEA) techniques. Patients were randomised into two groups according to the type of suture material used. In Group A, absorbable suture material (polyglycolic acid) was used and in Group B non-absorbable suture material (polypropylene) was used. Primary end-point was to compare severe restenosis and aneurysmal formation rates between the two groups of patients. For statistical analysis only cases with a minimum period of follow-up of 12 months were considered. Results: A total of 868 surgical procedures were considered for data analysis. Median follow-up was 6 years (range 1-10 years). The rate of postoperative complications was better for group A for both cCEA and eCEA procedures: 3.5 % and 2.0 % for group A, respectively, and 11.8 % and 12.9 % for group B, respectively. Conclusions: In carotid surgery, the use of absorbable suture material seems to be safe and effective and with a general lower complications rate compared to the use of non-absorbable materials.

scholarly journals Obstructive pneumonia owing to migration of a Teflon pledget at 8 years after surgery for a pulmonary carcinoid tumor: a case report

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Hikaru Watanabe ◽  
Kohei Abe ◽  
Naoki Kanauchi
Keyword(s):  
General Anesthesia ◽  
Carcinoid Tumor ◽  
Suture Material ◽  
Rare Complication ◽  
Absorbable Suture ◽  
Suture Materials ◽  
Bronchial Stump ◽  
Flexible Bronchoscope ◽  
Pulmonary Carcinoid ◽  
Bronchial Lumen

Abstract Background It is uncommon for a bronchial stump-related complication to develop during the remote postoperative period in a case of obstructive pneumonia owing to migration of the suture material. Here, we describe a case of bronchial obstructive pneumonia that developed owing to migration of the suture material in the airway 8 years after pulmonary resection. Case presentation A 34-year-old woman underwent left lower lobectomy for a pulmonary carcinoid tumor (pT1bN0M0-stage IA) in 2010. She experienced obstructive pneumonia, and chest computed tomography revealed a mass protruding from the bronchial stump to the bronchial lumen in 2018. After treatment for pneumonia, flexible bronchoscopy showed the presence of a fibrous suture material (Teflon pledget) completely obstructing the left second carina. A week later, the Teflon pledget obstructing the bronchial lumen was removed using a flexible bronchoscope with the patient under general anesthesia. The procedure was completed without removing the small amount of granulation tissue because the bronchial lumen opened after removing the Teflon pledget. She has remained asymptomatic for 1 year after removal. Conclusions In this case, the complication of obstructive pneumonia developed owing to migration of the non-absorbable suture materials used to suture the bronchial stump. Bronchoscopic management of this rare complication comprised endobronchial removal with the patient under general anesthesia. Given our experience with this case, we believe that such conservative management should allow for excellent results in most instances and avoid the need for reoperation.

scholarly journals Identification of the LLDPE Constitutive Material Model for Energy Absorption in Impact Applications

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1537
Author(s):  
Luděk Hynčík ◽  
Petra Kochová ◽  
Jan Špička ◽  
Tomasz Bońkowski ◽  
Robert Cimrman ◽  
...  
Keyword(s):  
Strain Rate ◽  
Material Model ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Stress Strain ◽  
Rate Dependent ◽  
Constitutive Material Model ◽  
Principal Directions ◽  
Constitutive Material

Current industrial trends bring new challenges in energy absorbing systems. Polymer materials as the traditional packaging materials seem to be promising due to their low weight, structure, and production price. Based on the review, the linear low-density polyethylene (LLDPE) material was identified as the most promising material for absorbing impact energy. The current paper addresses the identification of the material parameters and the development of a constitutive material model to be used in future designs by virtual prototyping. The paper deals with the experimental measurement of the stress-strain relations of linear low-density polyethylene under static and dynamic loading. The quasi-static measurement was realized in two perpendicular principal directions and was supplemented by a test measurement in the 45° direction, i.e., exactly between the principal directions. The quasi-static stress-strain curves were analyzed as an initial step for dynamic strain rate-dependent material behavior. The dynamic response was tested in a drop tower using a spherical impactor hitting a flat material multi-layered specimen at two different energy levels. The strain rate-dependent material model was identified by optimizing the static material response obtained in the dynamic experiments. The material model was validated by the virtual reconstruction of the experiments and by comparing the numerical results to the experimental ones.

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