Habiba Bougherara

Toronto Metropolitan University

A 3D progressive fatigue damage model was incorporated into ABAQUS software to predict the fatigue life of hybrid carbon-flax-epoxy composites. A cohesive zone method was employed to simulate delamination damage at carbon/flax interface. To evaluate the accuracy of the finite element model, two different layups, namely, unidirectional [0–90 C2 /0 F...

Comminuted proximal humerus fractures are often repaired by metal plates, but potentially still experience bone refracture, bone “stress shielding,” screw perforation, delayed healing, and so forth. This “proof of principle” investigation is the initial step towards the design of a new plate using alternative materials to address some of these prob...

This research investigates the effects of hybridization with flax in two distinct laminates: Kevlar/flax (Kevlar/flax/epoxy, KFE) and glass/flax (glass/flax/epoxy, GFE), each featuring two flax fiber orientations (0° and ±45°) under stress-controlled conditions. Employing the wet hand lay-up method, the laminates, comprising 16 plies in a sandwich...

Bone fracture plates are usually made from steel or titanium, which are much stiffer than cortical bone. This may cause bone ‘stress shielding’ (i.e. bone resorption leading to plate loosening) and delayed fracture healing (i.e. fracture motion is less than needed to stimulate callus formation at the fracture). Thus, the authors previously designed...

Currently, there is no established finite element (FE) method to apply physiologically realistic loads and constraints to the humerus. This FE study showed that 2 'simple' methods involving direct head loads, no head constraints, and rigid elbow or mid-length constraints created excessive stresses and bending. However, 2 'intermediate' methods invo...

Phantoms with tissue-mimicking properties play a crucial role in the calibration of medical imaging modalities, including Magnetic Resonance Imaging (MRI). Among these phantoms, silicone-based ones are widely used due to their long-term stability in MR imaging. Most of these phantoms are manufactured using traditional pour-mold techniques which oft...

This paper presents experimental investigations on the fatigue behavior of Flax, Kevlar, and Kevlar/Flax-reinforced epoxy specimens under accelerated step loading. The samples consisted of a 12-ply-Flax core in a sandwich structure surrounded by a two-layer Kevlar skin, and they were tested under tension–tension progressive cyclic loading. The fati...

The failure of polymethyl methacrylate (PMMA) orthopedic cement is considered the most important problem in total hip arthroplasty and eventual prosthesis loosening. Fiber or particulate reinforcement has been used to improve the mechanical properties of bone cement. However, reinforced cements have also been limited by adhesion between the PMMA an...

Additive manufacturing, commonly referred to as 3D printing, is a rapidly growing technology that allows for the creation of three-dimensional parts in a fraction of the time required by traditional methods. Conventional 3D printers use either cartesian or delta mechanisms, which are reliable but limited in movement due to the fixed orientation of...

Hybrid composites offer a viable alternative to conventional composites in terms of reduced cost and environmental impact. This study investigated the effect of hybridizing flax with Kevlar on the flexural and impact properties of Kevlar/flax/epoxy composites using three-point bending, drop-weight, and Charpy impact tests. The tested specimens were...

The fused deposition modeling (FDM) technique is widely used to produce components for various applications and has the potential to revolutionize orthopedic research through the production of custom-fit and readily available biomedical implants. The properties of FDM-produced implants are significantly influenced by processing parameters, with lay...

Composites reinforced with plant fibers have a high potential for valorization in new industrial applications, due to their good specific mechanical characteristics, their low cost and their availability. In order to accelerate their wide use in the industrial field, it is essential to improve their behaviour and durability in longterm atmospheric...

Most of the research on hybrid natural fiber composites has been focused on non-structural applications. The aim of this research is to improve the understanding of how to use hybrid natural fiber composites for structural applications, such as in the aerospace and automotive industries. The joining of subassemblies with rivets, bolts, or screws is...

A finite element model that incorporates a 3D progressive fatigue damage model (3D PFDM) is developed to simulate the fatigue behavior of Flax-epoxy (FE) composites. Input parameters of the model are determined from testing the material properties in all directions. A double-notched shear test is used to characterize the out-of-plane shear properti...

Many engineering applications using composite materials require an assembly of components which can be accomplished using adhesives, welding, or fasteners. The last requires the machining of holes, which are usually done via conventional drilling or abrasive water jet process. The choice of the machining process is important because it has a direct...

Recent research showed that strain-controlled (constant strain-amplitude) cycling may be ideal for natural-fibre-composite (NFC) fatigue testing, since enforcing constant strain-rates eliminate the apparent modulus ‘improvement’ reported by several stress-controlled studies. This article re-examines Flax-reinforcement as an alternative to Glass by...

Aseptic loosening due to the progressive periprosthetic bone resorption following total hip replacement is a crucial concern, that causes complications and failure of the arthroplasty surgery. The mismatch in stiffness between the hip implant and the surrounding femoral bone is one of the key factors leading to bone density resorption. This paper a...

This is a study to quantify damage progression of a new Kevlar/flax/epoxy (KFE) hybrid composite made with 12 layers of pure flax fiber fabric sandwiched between 4 layers of pure Kevlar fiber weave. There were four versions of the composite: 0° unidirectional, 0°/90° cross-ply, ± 45° angle-ply flax fibers, and Kevlar fibers-only as the control. Com...

Fused deposition modeling (FDM) is one of the most popular and ubiquitous additive manufacturing methods, which uses a layering procedure to build 3D models layers-upon-layers. Since the layers are the constituents of the resulted 3D part, the layering process can directly affect the part’s surface finish and mechanical properties, which are the tw...

The influence of conventional drilling (CD) and abrasive water jet (AWJ) machining on the mechanical behavior of hybrid carbon/flax composites was investigated. The specimens were manufactured using woven carbon fiber (C) and unidirectional flax fiber (F) in three configurations: unidirectional [0-90C2/0F6]S, cross-ply [0-90C2/(0/90)F6]S, and angle...

The influence of the drilling parameters and the stacking sequence of flax/epoxy composite laminate on the cutting force and the damage induced were studied experimentally and numerically. Drilling tests were carried out based on full experimental design and the delamination at the entry and exit of the hole were quantified using an optical microsc...

In this study, we demonstrate a design of a stable bi-layer coating configuration on UHMWPE fibres surface. UHMWPE fibres show abundant promise as load bearing reinforcement in fibre-based composites; however, its inert chemical nature has been a consistent hurdle for developing high performance composites. An efficient and environmentally friendly...

The impact behaviour of woven kevlar fibre/flax fibre/epoxy (WK-F-E) hybrid composites that is made of 12 layers of flax fibres (F) sandwitched in 4 layers of plain-woven Kevlar 49 fibres (WK) is investigated via the use of two configurations: woven Kevlar/unidirectional flax/epoxy [0-902K/06F]S (WK-UDF-E) and woven Kevlar/cross-ply flax/epoxy [0-9...

This paper experimentally examines the influence of abrasive water jet (AWJ) machined holes on the mechanical performance and damage evolution of flax/epoxy and carbon/flax/epoxy hybrid composites. The specimens were made of unidirectional flax fiber (F) and woven carbon fiber (C) in four configurations: unidirectional flax [0 F]16 (UD-F), unidirec...

This is the first study on the fatigue tensile performance of a novel hybrid composite made as Type A (i.e. woven carbon fibers plus unidirectional flax fibers [W C2 /0 F12 /W C2 ]) or Type B (i.e. woven carbon fibers plus oblique flax fibers [W C2 /(±45) F6S /W C2 ]) in epoxy resin. Composite plates were examined under constant strain amplitude us...

This research work presents a comparative study of the tensile properties of polylactic acid (PLA) specimens per ASTM D638-14 fabricated by compression molding and 3D printing. PLA pellets from one batch are used in compression molding and filament extrusion for 3D printing. The compression molding process parameters are optimized to obtain an uppe...

A finite element model that incorporates the progressive fatigue damage model (PFDM) is developed to predict the fatigue life of Flax-epoxy composites with [0]16, [90]16, [0/90]4S, [±45]4S and Quasi-isotropic [0/+45/90/-45]2S layups under strain-controlled conditions. A stochastic distribution method is used to consider the manufacturing-induced va...

This finite element study optimized far cortical locking (FCL) technology for early callus formation in distal femur fracture fixation with a 9-hole plate using FCL screws proximal to, and standard locking screws distal to, the fracture. Analyses were done for 120 possible FCL screw configurations by varying FCL screw distribution and number. A hip...

The use of temporary hip prosthesis made of orthopedic cement (spacer) in conjunction with antibiotics became a widespread method used for treating prosthetic infections despite the fact that this method makes bone cement (PMMA) more fragile. The necessity to incorporate reinforcement is therefore crucial to strengthen the bone cement. In this stud...

Compressive mechanical testing was performed on continuous fiber Flax/Epoxy laminate specimens, capturing, and quantifying its evolving in-plane plasticity and moduli. This non-linear behaviour was simulated using a modified continuum damage mechanics-based model. The standard Mesoscale Damage Theory (MDT) of Ladeveze and Le Dantec was modified to...

This proof-of-concept study designs distal femur fracture plates from semi-rigid materials vs. traditional metals for toe-touch weight-bearing recommended to patients immediately after surgery. The two-fold goal was to (a) reduce stress shielding (SS) by increasing cortical bone stress thereby reducing the risk of bone absorption and plate loosenin...

The mode II interlaminar fracture toughness characteristics of flax/glass/epoxy hybrid laminates were experimentally and numerically examined. Three types of hybrid composites that are made of flax (F) and glass (G) and with different layup sequences (i.e., Hybrid I [0 G/0 F]8S, Hybrid II [04G/04F]S, and Hybrid III [04G/(90/0)2F]S) were investigate...

Ultrahigh molecular weight polyethylene (UHMWPE) fiber is considered as an ideal reinforcing component due to its high strength-to-weight ratio, good toughness and high chemical and wear resistance. However, poor interfacial adhesion with polymer matrices has hindered the development of UHMWPE-based composites with high performance. This review is...

This study provides the first biomechanical comparison of the fixation constructs that can be created to treat transverse acetabular fractures when using the “gold-standard” posterior versus the anterior approach with and without a total hip arthroplasty in the elderly. Synthetic hemipelvises partially simulating osteoporosis (n = 24) were osteotom...

Natural fibers are inexpensive, biodegradable, and similar specific properties to some synthetic fibers. Hardly any previous investigations exist of a composite made of multiple layers of pure Kevlar fiber fabric and pure Flax fiber fabric in a “sandwich structure”, but it only measured impact properties. The composite was made of 12 Flax/epoxy lay...

Metallic intramedullary nails are the “gold standard” implant for repairing femur shaft fractures. However, their rigidity may eliminate axial micromotion at the fracture (causing delayed healing) and they may carry too much load relative to the femur (causing “stress shielding”). Consequently, some researchers have proposed fiber-reinforced compos...

Fatigue longevity and evolving material properties of Flax-epoxy laminates is examined under constant strain amplitude cycling. Several recent fatigue studies on Flax-composites, all of which were conducted under stress-control, found that certain laminates demonstrate a modulus increase over fatigue life, even while accumulating internal damage an...

Composites reinforced with plant‐based fibers present a high potential for valorization in new industrial applications due to their good specific mechanical characteristics, renewability, and recyclability. In order to accelerate their wide industry adoption, it is critical to assess their behavior and durability in heat and humid environments. Thi...

Many researchers have experimentally evaluated the mechanical characteristics of flax-based laminates to understand their behaviour under different loading conditions; however, doing so required significant investment in time, money and other resources. An alternative solution is to use advanced numerical and computational tools like FEA. In this s...

Ultra-High Molecular Weight Polyethylene (UHMWPE) is the gold standard biomaterial used as a bearing surface in total joint replacement surgeries. However, osteolysis and subsequent implant failure as a result of the production of wear debris may occur at the contacting surfaces. One potential solution to overcome this problem is to strengthen the...

Damage under progressive load–unload until failure was assessed for a new woven carbon fibre/flax fibre/epoxy hybrid composite via stiffness degradation D, permanent strain ɛp, and crack density ρc. Type A configuration had woven carbon fibres and unidirectional flax fibres (i.e. [0–90C2/0F12/0–90C2]), while Type B configuration had woven carbon fi...

This study characterized the static and fatigue compressive properties of a new hybrid composite material made of synthetic and natural fibers with an epoxy matrix. The glass/flax/epoxy composite material was manufactured as a “sandwich structure” with a Type A configuration (i.e. [0 G2 /0 F12 /0 G2 ] using unidirectional glass (G) and flax (F) fib...

This chapter was aimed to enlighten readers on topics concerning machining natural fiber composites, mainly drilling. This study summarizes the challenges faced during machining natural fiber composites and defects observed. Delamination (both entry and exit), burrs, uncut fibers, fiber matrix debonding and uncut fibers are the predominant damage t...

This investigation assessed the biomechanical performance of the metal plate and bone strut technique for fixing recalcitrant nonunions of femur midshaft segmental defects, which has not been systematically done before. A finite element (FE) model was developed and then validated by experiments with the femur in 15 deg of adduction at a subclinical...

This study is the first to characterize the impact properties of a new hybrid composite made with woven carbon fibres plus unidirectional (i.e. Type A) or cross-ply (i.e. Type B) flax fibres in an epoxy matrix. A pendulum impact tester applied a range of impact energies (5–40 J) to a series composite plates, which were assessed using photographic,...

This study characterized the mechanical, morphological, and water absorption properties of a new hybrid composite material made of a Type A configuration (i.e. [0–90C2/0F12/0–90C2]) of 4 harness satin woven carbon fibres (i.e. alternating fibre bundles in a 3 over/1 under weave with bundles at 0° and 90°) plus commercially designated “unidirectiona...

Purpose: To compare the stresses at bone-arthroplasty interface of constrained and semi-constrained knee prostheses, using the finite element (FE) method as a predictor of the survivorship of the implants. Methods: Three-dimensional FE models of the knee implanted with rotating hinge (RHK) and legacy constrained condylar (LCCK) prostheses were g...

With the resurgence of natural fibers as a viable alternative to synthetic fibers, there is a need to study their mechanical behaviour under different modes of loading. In this research, flax/epoxy composite laminates were manufactured and tested under low velocity impact loading to study the damage development on the laminates and assess their cap...

This is the first study, to the authors' knowledge, to simultaneously perform a direct comparison of finite element analysis, strain gage measurements, and infrared thermography for stress analysis under both static and dynamics tensile loads of the classic geometry of a composite plate with a center hole. The plate was made from a carbon fiber-rei...

In this paper, the dynamic response of functionally graded nanocomposite beams under the action of a moving load are investigated. Three different types of Carbon NanoTubes (CNT's) distributions in a polymer matrix material are studied; Uniform Distribution (UD), Symmetrically Functionally Graded (SFG) distribution and Unsymmetrically Functionally...

Existing extension–twist coupling in composite tubes can result in undesirable deformations, which may in turn interfere with their normal performance. In this work, a quantitative factor was developed to examine the existence of such coupling in circular composite tubes using the non-classical composite beam theory. The theoretical formulation con...

A novel micromechanical approach is proposed to calculate the effective thermal conductivities of fiber reinforced composite materials. The key advantage of the present formulation is its ability to yield closed form solutions for the effective thermal conductivity of composites in both longitudinal and transverse directions for three dimensional h...

This is the first study to quantify the measurement error due to the physical thickness of Fujifilm for several material combinations relevant to orthopaedics. Theoretical and experimental analyses were conducted for cylinder-on-flat indentation over a series of forces (750 and 3000 N), cylinder diameters (0 to 80 mm), and material combinations (me...

Acetabular fractures potentially account for up to half of all pelvic fractures, while pelvic fractures potentially account for over one-tenth of all human bone fractures. This is the first biomechanical study to assess acetabular fracture fixation using plates versus cables in the presence of a total hip arthroplasty, as done for the elderly. In P...

The influence of conventional drilling (CD) and abrasive water jet (AWJ) cutting on the fatigue performance of carbon fabric/epoxy plates was investigated. Observations of machined hole regions revealed more severe damage on the CD hole surfaces with larger damage regions penetrating into the material. For both material systems investigated, the su...

A continuum damage mechanics based mesoscale model is developed within a thermodynamics framework to describe the in-plane tensile response in natural fibre composites. The standard Mesoscale Damage Theory (MDT) is modified to incorporate damage and inelasticity evolution in the fibre-direction, thereby capturing the unique nonlinear fibre-directio...

Human articulating joints (e.g., shoulder, hip, knee) are junctions of two cartilage-covered bones moving against each other at a common interface. Joints help transfer loads from bone to bone to permit human movement. However, osteoarthritis is a disease that damages cartilage, resulting in bone-on-bone articulation, which is painful and debilitat...

Experimental stress analysis of whole bones, implants, and whole bone–implant constructs is an important approach in orthopaedic biomechanics. High stresses in whole bones and implants may cause mechanical failure, but low stresses in whole bone may cause “stress shielding,” which leads to bone atrophy, bone resorption, and implant loosening. Surfa...

Conservative hip implants preserve healthy bone for revision surgeries and improve physiological loading; however, they have little supporting biomechanical data with respect to their 3D orientation during implantation. This study endeavored to determine the optimal 3D orientation of a straight short stem hip implant within the proximal femur that...

Composite reinforcement by natural fibres like Flax do not enjoy the same popularity in engineering design as Carbon or Glass fibres on account of the relatively immature mechanical data on Flax-composites. Tensile and compressive mechanical properties are determined for Flax-fibre-reinforced-Epoxy composite. Damaged response is followed through SE...

Unstable intertrochanteric fractures are commonly treated with a cephalomedullary nail due to high failure rates with a sliding hip screw. The Omega3 Trochanteric Stabilizing Plate is a relatively new device that functions like a modified sliding hip screw with a proximal extension; however, its mechanical properties have not been evaluated. This s...

The purpose of this study is to investigate the mechanical feasibility of a hybrid Glass/Flax/Epoxy composite material for bone fracture fixation such as fracture plates. These hybrid composite plates have a sandwich structure in which the outer layers are made of Glass/Epoxy and the core from Flax/Epoxy. This configuration resulted in a unique str...

Short-stem hip implants are increasingly common since they preserve host bone stock and presumably reduce stress shielding by improving load distribution in the proximal femur. Stress shielding may lead to decreased bone density, implant loosening, and fracture. However, few biomechanical studies have examined short-stem hip implants. The purpose o...

This chapter discusses the influence of the machining process and machining parameters during machining of composite materials. In the first time, the chapter summarizes reviews of the machining processes and its impact on the mechanical behavior of composite materials. In the second time, a characterization of the surface defects induced by differ...

Although bone fracture plates can provide appropriate stability at the fracture site and lead to early patient mobilization, they significantly change the loading pattern in the bone after union (Stress shielding). This phenomenon results in a bone density decrease, which may cause premature failure of the implant. This paper presents the first stu...

In this research paper, the influence of two drilling processes on the mechanical behavior of bolted composite joints was investigated. Two stacking sequences were studied namely, [±45°]2S and [90/+45/0/−45]S. The composite specimens were drilled using conventional machining (CM) and abrasive water-jet machining (AWJM). Fatigue tests combined with...

The high stiffness of conventional intramedullary (IM) nails may result in stress shielding and subsequent bone loss following healing in long bone fractures. It can also delay union by reducing compressive loads at the fracture site, thereby inhibiting secondary bone healing. This paper introduces a new approach for the optimization of a fiber-rei...

The present study introduces a progressive fatigue damage model within a multiscale framework by incorporating a Simplified Unit Cell Micromechanical model into a Finite Element program. The use of micromechanics will allow the study of damage at the micro-scale which can therefore identify modes of failure in each of the composite’s constituents,...

A composition suitable for bone replacement is provided. The composition is a nanocomposite matrix, resembling both the structure and the properties of natural bone, including morphology, composition and mechanical characteristics. The nanocomposite is preferably porous and comprises:(1) micro or nano scale cellulose crystals or fibres;(2) hydr...

Cisplatin (CisPt) is a commonly used platinum-based chemotherapeutic agent. Its efficacy is limited due to drug resistance and multiple side effects, thereby warranting a new approach to improving the pharmacological effect of CisPt. A newly developed mathematical hypothesis suggested that mechanical loading, when coupled with a chemotherapeutic dr...

The main objective of this preliminary investigation is to identify and characterize the damage evolution of angle ply ([±45] 16 ) flax-reinforced epoxy composites using an energy-based damage model combined with Scanning Electron Microscopy (SEM) observations. The damage model’s parameters for the flax-reinforced epoxy composite were determined fr...

This study is part of an ongoing program to develop a new CF/Flax/Epoxy bone fracture plate to be used in orthopedic trauma applications. The purpose was to determine this new plate's in-vitro effects on the level of bone formation genes, as well as cell viability in comparison with a medical grade metal (i.e. stainless steel) commonly employed for...