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Full-Text Articles in Engineering

A Method Of Assessing Peripheral Stent Abrasiveness Under Cyclic Deformations Experienced During Limb Movement, Courtney Keiser, Kaspars Maleckis, Pauline Struczewska, Majid Jadidi, Jason N. Mactaggart, Alexey Kamenskiy Nov 2022

A Method Of Assessing Peripheral Stent Abrasiveness Under Cyclic Deformations Experienced During Limb Movement, Courtney Keiser, Kaspars Maleckis, Pauline Struczewska, Majid Jadidi, Jason N. Mactaggart, Alexey Kamenskiy

Department of Mechanical and Materials Engineering: Faculty Publications

Poor outcomes of peripheral arterial disease stenting are often attributed to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our goals were to develop a method of assessing the abrasiveness of peripheral nitinol stents and apply it to several commercial devices. Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera stents were deployed inside electrospun nanofibrillar tubes with femoropopliteal artery-mimicking mechanical properties and subjected to cyclic axial compression …


Effect Of Indentation On Sandwich Composite Structure Mechanical Behavior, Marius V. Jatulis Mar 2022

Effect Of Indentation On Sandwich Composite Structure Mechanical Behavior, Marius V. Jatulis

Master's Theses

Composite sandwich structures are prevalent in engineering applications where high strength to weight ratios are critical. A composite sandwich includes the addition of a core material between two composite face sheets to increase ultimate stress in compression and bending loading cases. The performance of many composite sandwich structure configurations is well understood in the undamaged case. This analysis examines a type of damage, low velocity indentation, and determines the effect on mechanical behavior. The scope of the analysis includes manufacturing sandwich composite structures, creating indentation in the composite, and testing the sandwich composite structure. The mechanical behavior of the composite …


Implementation Of Multiscale Mechanisms In Finite Element Analysis Of Active Composite Structures, Amany G. Micheal Prof., Yehia Bahei El Din Prof. Feb 2022

Implementation Of Multiscale Mechanisms In Finite Element Analysis Of Active Composite Structures, Amany G. Micheal Prof., Yehia Bahei El Din Prof.

Centre for Advanced Materials

Composite structures reinforced with electrically active filaments are modeled with the finite element method while the underlying thermo-electromechanical coupling phenomena and damage are taken into consideration. At the outset, structural analysis is performed with a general-purpose finite element code and a special material routine, which propagates local phenomena to the overall scale is utilized. The material routine implements an interactive, multiscale analysis, which provides seamless integration of the mechanics at the composite’s micro, macro, and structural length scales. The interface between the multiscale material routine and the finite element code is made through nonmechanical strains caused by damage, and piezo/pyro-electric …


Implementation Of Multiscale Mechanisms In Finite Element Analysis Of Active Composite Structures, Amany Micheal, Yehia Bahei-El-Din Jan 2022

Implementation Of Multiscale Mechanisms In Finite Element Analysis Of Active Composite Structures, Amany Micheal, Yehia Bahei-El-Din

Centre for Advanced Materials

Interrogation of composite structures for inherent damage is investigated by implementing a three-tier analysis scheme. The analysis starts at the structure level where a general-purpose Finite Element code ABAQUS is employed to obtain the stress field in the second level of analysis which is the composite laminate. A special material routine is prepared to propagate the local fields to the individual plies and hence to the third level of analysis which is the microstructure modeling of the composite. Through the third level of analysis, interface damage between fiber and matrix is checked implementing a certain failure criteria. The interaction between …


A Coupled Viscoplastic-Damage Constitutive Model For Semicrystalline Polymers, Jeffrey Wiersma Jan 2022

A Coupled Viscoplastic-Damage Constitutive Model For Semicrystalline Polymers, Jeffrey Wiersma

Dissertations, Master's Theses and Master's Reports

The ease of processing, recyclability, and ideal cost to weight ratio makes the semi-crystalline polymers attractive in the aerospace, automotive, and defense industries. Use of semicrystalline polymers for engineering design requires a thorough understanding of their response to mechanical deformation, rate of loading, temperature, and failure mechanisms. However, there lacks a generally agreed upon constitutive model to capture the large deformation elastic-viscoplastic response of semicrystalline polymers while incorporating the strain-rate dependence and damage behavior. To address this aspect, the objective of this dissertation is to develop an elastic-viscoplastic constitutive model to predict the rate dependent, large deformation response of semicrystalline …