Braided Fiber Research Articles

組紐製小口径絹人工血管の作製とイヌ腹部大動脈移植による評価

The small-diameter (less than 6.0 mm in diameter) vascular grafts are highly desired due to a large demand of surgical revascularization. In this study, a small-diameter (6mm) vascular graft was prepared with braided Bombyx mori silk fiber tube coated by B. mori silk fibroin aqueous solution, with the goal of achieving sufficient physical strength and good patency of long term. The mechanical properties were evaluated by circumferential tensile test and suture strength test, indicating that the properties were improved remarkably by silk coating. The braiding silk fibroin graft was also evaluated by implantation into the dog abdominal aorta. The color doppler sonography after implantation for 11 months showed that there are neither dilatation nor constriction. At 2 years after implantation of the grafts in dog abdominal aorta, the graft patency and endothelial cell lining of the lumen surfaces were observed. These results demonstrate the feasibility of using braiding silk fibroin vascular graft as a small diameter vascular graft with long term patency.

Three-Degree-of-Freedom MR-Compatible Multisegment Cardiac Catheter Steering Mechanism

This paper presents a novel MR-compatible 3-DOF cardiac catheter steering mechanism. The catheter's steerable structure is tendon driven and consists of miniature deflectable, helical segments created by a precise rapid prototyping technique. The created catheter prototype has an outer diameter of 9 Fr (3mm) and a steerable distal end that can be deflected in a 3-D space via four braided high-tensile Spectra fiber tendons. Any longitudinal twist commonly observed in helical structures is compensated for by employing clockwise (CW) and counter clockwise (CCW) helical segments in an alternating fashion. A 280μm flexible carbon fiber rod is used as a backbone in a central channel to improve the structure's steering and positioning repeatability. In addition to the backbone, a carbon fiber tube can be inserted into the structure to a varying amount capable of changing the structure's forcibility and, thus, providing a means to change the curvature and to modify the deflectable length of the catheter leading to an extension of reachable points in the catheter-tip workspace. A unique feature of this helical segment structure is that the stiffness can be further adjusted by appropriately tensioning tendons simultaneously. An experimental study has been conducted examining the catheter-tip trajectory in a 3-D space and its positioning repeatability using a 5-DOF magnetic coil tracking system. Furthermore, MRI experiments in a 1.5-T scanner confirmed the MR-compatibility of the catheter prototype. The study shows that the proposed concept for catheter steering has great potential to be employed for robotically steered and MR-guided cardiac catheterization.

Strength analysis of three-dimensional braided T-shaped composite structures

In this paper, based on the properties and strength analysis of the prestressed unit cell, the pull-off behaviors of the three-dimensional (3D) braided T-shaped composite structures are estimated by means of finite element method (FEM). First, a finite element model with Hashin’s failure criterion and maximum stress failure criterion is established to investigate the influence of the prestresses on the strength of the unit cell for the 3D four-directional braided composites. Second, the influences of the braided direction and fiber content on the strength of the unit cell for the 3D four-directional braided composites are discussed. Finally, based on the predicting results of the unit cell strength, the pull-off strength and damage characterizations of the 3D braided T-shaped composite structures is predicted using the Tsai–Hill failure criterion. The results will provide an important guidance for designing and evaluating damage and strength the 3D braided T-shaped composite structures.

Type I collagen and polyvinyl alcohol blend fiber scaffold for anterior cruciate ligament reconstruction

The aim of this study was to perform an evaluation of a braided fiber scaffold for anterior cruciate ligament (ACL) reconstruction. The scaffold was composed of 50% type I collagen (Col-I) and 50% polyvinyl alcohol (PVA). First, the biocompatibility and in vitro weight loss of the scaffold were tested. Then, the scaffolds were used to reconstruct the ACL in China Bama mimi pigs. At 24 weeks post-operation, the mechanical properties and histology of the regenerated ACL were analyzed. The maximum load and tensile strength were 472.43± 15.2 N and 29.71± 0.96 MPa, respectively; both were ∼75% of those of native ACL and ∼90% of those of fiber scaffold. This indicated that the scaffold maintained a large portion of native ACL's mechanical properties, and tissue formation on the scaffold compensated most of the tensile strength loss caused by scaffold degradation. Histology and immunohistology analysis showed the morphology and major extracellular matrix components of the regenerated ligament resembled the native ACL. Thus, the Col-I/PVA blend fiber ACL scaffold showed good potential for clinical applications.

Preparation and bending properties of three dimensional braided single poly (lactic acid) composite

New three dimensional (3D) braided single poly (lactic acid) composites (PLA–SPCs) were obtained by combining 3D and five (5)-direction braiding technique and hot-compression technical process. 3D and 5-direction braided preforms with different braiding angles, thicknesses and fiber volume fractions were prepared. Preforms were preheated in the specially designed die system in order to make all of the fibers partially melted. In the next stage, the preforms were consolidated under a certain pressure (from 7.8 to 10MPa) at temperatures ranging from 130 up to 150°C. Under the controlled processing conditions, one part of fiber body formed matrix while the other part retained its fibrous form.At the same consolidation temperature, the maximum bending stress values resulted to be substantially dependent on the fiber volume fraction of PLA–SPCs, while the bending modulus values were largely subjected to the fiber content in the length direction. The increases of consolidation pressure gave rise to better fusion of neighboring fibers with the result that the maximum stress and modulus were increased. As the consolidation temperature increases, the fusion bonding was improved, the bending failure feature was converted from plastic to brittle, both maximum bending stress and modulus values were increased. It is expected that this study could provide a new approach for the manufacture of high-performance single polymer composites (SPCs) by using thermoplastic polymer fibers.

Effects of SiC contents on the dielectric properties of SiO2f/SiO2 composites fabricated through a sol-gel process

Abstract SiC powders have been synthesized through a combustion process using Si powders and carbon black as starting materials. As a C-enriched α-SiC solid solution, the prepared SiC powders contain antisite defects of CSi and graphite state of sp2C, revealing good real part e′ and imaginary part e″ of permittivity. Subsequently, SiO2f/SiO2 composites are fabricated via a sol-gel process employing three-dimensional braided quartz fiber fabrics as a skeleton and a mixture of high-purity silica sol and the synthesized SiC powders as slurry. The effects of the SiC contents on the dielectric properties of the composites are investigated. The real and imaginary parts of the complex permittivity (e′ and e″) of the composites increase first before they decrease with an increasing SiC content from 0 to 40 wt.%. The maximum e′ and e″ are obtained at the SiC content of 20 wt.% in the range of 8–18 GHz, and the bandwidth with the reflectivity below − 10 dB of the SiO2f/SiO2 composite with 20 wt.% SiC powders is 5 GHz, which can well meet the requirements as good microwave absorbing materials.

Sonochemical functionalization of mesoporous carbon for uranium extraction from seawater

Extracting uranium from seawater is challenging due to its low concentration (3.3 ppb) and the myriad of competing ions. Mesoporous carbon materials provide a high surface area alternative to the traditional polymeric fiber braids developed for seawater extractions, specifically uranium extraction. In this work, sonochemical grafting of acrylonitrile onto the pores of soft-templated mesoporous carbons followed by its conversion to amidoxime functionalities was used to prepare an effective sorbent material with a high density of binding sites. Pore blockage, often observed for free radical polymerization, leads to poor adsorbent performance but can be easily overcome by the use of ultrasound during polymerization. Parameters such as surface area and surface pre-treatment, sonication intensity, solvent system, and monomer/initiator ratios were varied to optimize the polymerization and uranium adsorption capacity while not blocking the porosity, a significant hurdle in the utilization of functionalized porous materials. The results show that neither the surface oxidation with nitric acid nor CO2 activation alone is sufficient to cause significant improvement in grafting and uranium uptake. However, when coupled together, a greatly enhanced performance of the adsorbent materials was observed.

Bending behavior of concrete-filled tubular FRP arches for bridge structures

Concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) are seeing increasing use in various infrastructure applications. This paper investigates the bending response of CFFTs for buried arch bridge structures. The thin-walled hybrid composite tubes developed at the University of Maine are fabricated from a combination of E-glass and carbon fiber braid infused with vinyl ester resin. The composite tubes function as confinement, tension and shear reinforcing, eliminating the need for conventional steel rebar. Additionally, the tubes serve as stay-in-place formwork, reducing construction time and complexity relative to conventional cast-in-place concrete structures. The objectives of this study are to experimentally assess the bending response of the concrete-filled FRP arches, compare test results with an analytical model, and illustrate the field application of this technology. To achieve these objectives, the bending load–deformation and moment–curvature response of CFFTs were investigated through quasi-static laboratory testing of three beams and four arches. The specimens were instrumented with displacement transducers and strain gauges at several locations. Two additional arches were subjected to 2,000,000 fatigue cycles and subsequently loaded to failure to assess the effect of fatigue on capacity. A nonlinear beam finite-element model that accounts for concrete confinement and cracking is presented. Model-predicted load–deformation and moment–curvature behavior as well as specimen capacity are shown to compare well with measured data from the arch testing, with arch capacity predicted within 4.2% of the average measured failure load.

Mechanical properties and mechanical behavior of (SiO2)f/SiO2 composites with 3D six-directional braided quartz fiber preform

Abstract(SiO2)f/SiO2 composites reinforced with three-dimensional (3D) six-directional preform were fabricated by the silicasol-infiltration-sintering method. The nominal fiber volume fraction was 47%. To characterize the mechanical properties of the composites, mechanical testing was carried out under various loading conditions, including tensile, flexural, and shear loading. The composite exhibited highly nonlinear stress-strain behavior under all the three types of loading. The results indicated that the 3D six-directional braided (SiO2)f/SiO2 composites exhibited superior flexural properties and good shear resistant as compared with other types of preform (2.5D and 3D four-directional)-reinforced (SiO2)f/SiO2 composites. 3D six-directional braided (SiO2)f/SiO2 composite exhibited graceful failure behavior under loading. The addition of 5th and 6th yarns resulted in controlled fracture and hence these 3D six-directional braided composites could possibly be suitable for thermal structure components.

Experimental characterization of transverse impact behaviors of four-step 3-D rectangular braided composites

This paper reports experimental results of the transverse impact behaviors of four-step three-dimension carbon/epoxy rectangular braided composite. We employed Split Hopkinson Pressure Bar apparatus to test the transverse impact behaviors. The impact load-displacement curves and impact damages of the braided composite were recorded to analyze the energy absorptions and the impact damage mechanisms. The quasi-static indentation tests and drop-weight impact tests were also performed to compare with those in transverse impact tests. It was found that the failure area and energy absorption is increased as the increase of impact velocity and the failure area is in a saw tooth shape owing to the breakage of the braided fiber tows.

Fracture Resistance of Composite Fixed Partial Dentures Reinforced with Pre-impregnated and Non-impregnated Fibers.

Background and aims The mechanical properties of fiber-reinforced composite fixed partial dentures (FPDs) are af-fected by fiber impregnation. The aim of this in vitro study was to compare the fracture resistance of composite fixed partialdentures reinforced with pre-impregnated and non-impregnated fibers. Materials and methods Groups (n=5) of three-unit fiber-reinforced composite FPDs (23 mm in length) from maxillary second premolar to maxillary second molar were fabricated on two abutments with pontic width of 12 mm. One group was fabricated as the control group with composite (Gradia) and the other two groups were fabricated with composite (Gradia) reinforced with pre-impregnated fiber (Fibrex ribbon) and non-impregnated fiber (Fiber braid), respectively. The specimens were stored in distilled water for one week at 37°C and then tested in a universal testing machine by means of a three-point bending test. Statistical analysis consisted of one-way ANOVA and a post hoc Scheffé’s test for the test groups (α=0.05). Results Fracture resistance (N) differed significantly between the control group and the other two groups (P<0.001), but there were no statistically significant differences between the pre-impregnated and non-impregnated groups (P=0.565). The degree of deflection measured (mm) did not differ significantly between the three groups (P=0.397), yet the mean deflection measured in pre-impregnated group was twice as that in the other two groups. Conclusion Reinforcement of composite with fiber might considerably increase the fracture resistance of FPDs; how-ever, the type of the fiber used resulted in no significant difference in fracture resistance of FPD specimens.

Utility of Polymer Cerclage Cables in Revision Shoulder Arthroplasty

Revision shoulder arthroplasty often requires humeral osteotomy for stem extraction or is complicated by periprosthetic fracture. In these situations, various modes of fixation are used, including cerclage wires, cable plates, and allograft strut augmentation. The use of metal wires and cables, however, has been associated with soft tissue irritation, sharps injuries, and accelerated wear of joint arthroplasty bearing surfaces. As an alternative to traditional metal cables, the SuperCable (Kinamed Inc, Camarillo, California) contains braided ultra-high molecular-weight polyethylene fibers surrounding a nylon core. To date, no studies have examined the use of nonmetallic cerclage cables in shoulder arthroplasty.A retrospective review was performed of 11 patients who underwent shoulder arthroplasty for which nonmetallic cerclage cables were used. Clinical and radiographic data were examined regarding patient age, procedure performed, indication for cerclage cabling, time to healing of osteotomy or fracture, and any complications associated with the use of these cerclage cables. Minimum follow-up was 1 year. Ten patients underwent reverse total shoulder arthroplasty, and 1 patient underwent revision unconstrained total shoulder arthroplasty. Mean follow-up was 20.5 months. Ten patients required humeral osteotomy for stem or cement removal. Allograft augmentation was performed in 7 patients. Mean time to healing was 3.2 months. No patients experienced loosening or migration of hardware or allograft, and no complications directly related to the use of nonmetallic cerclage cables were identified.

Efficient Multiscale Modeling Framework for Triaxially Braided Composites using Generalized Method of Cells

In this paper, a framework for a three-scale analysis, beginning at the constituent response and propagating to the braid repeating unit cell (RUC) level, is presented. At each scale in the analysis, the response of the appropriate RUC is represented by homogenized effective properties determined from the generalized method of cells micromechanics theory. Two different macroscale RUC architectures are considered, one for eventual finite-element implementation and the other for material design, and their differences are compared. Model validation is presented through comparison to both experimental data and detailed finite-element simulations. Results show good correlation within range of experimental scatter and the finite-element simulation. Results are also presented for parametric studies varying both the overall fiber volume fraction and braid angle. These studies are compared to predictions from classical lamination theory for reference. Finally, the multiscale analysis framework is used to predict t...

An enhanced static mathematical model of braided fibre-reinforced pneumatic artificial muscles

This paper presents a new static mathematical model of a type of pneumatic artificial muscle (PAM). Generally, there are three main kinds of PAM, of which the braided fibre-reinforced PAM is most common. The PAM produced by Festo Company (abbreviated as FMPAM in this paper) and McKibben muscle all belong to the category of braided fibre-reinforced PAM. However, the structure of FMPAM is different from that of McKibben muscle. In FMPAM, elastic material (elastomer) and braided reinforced fibres are mixed together. A quasi finite element method based on certain assumptions is suggested to derive the mathematic model via the elasticity principle of virtual work, in which the grid of every braided fibre is regarded as an element. By using such a method, it is possible to consider the elasticity of the braided fibres. Finally, a simplification and a compensation item are introduced to the static mathematical model. An experimental facility is set up to determine the tension—pressure—length character of the FMPAM in a quasi static experiment. The experimental results show that the new mathematical model developed in this paper can shed light on the static or quasi static character of FMPAM.

Characterization of Biaxial and Triaxial Braids: Fiber Architecture and Mechanical Properties

Biaxial and triaxial carbon fiber braids with off-axis braiding angles of 30°, 45° and 55° are characterized with respect to their fiber architecture. All braids are produced on a round mandrel with constant cross section. Detailed geometric information on the different braids, like roving dimensions, roving shapes and the degree of nesting is given. The findings from measurements in photomicrographs are used to construct meso-model yarn architectures at the unit cell level which are then analyzed with the WiseTex software (Lomov et al. Compos. Sci. Technol. 60:2083–2095, 2000). The results of the models’ analysis with TexComp and comparison of mechanical properties with tests are consistent and essential for further steps in predictive modeling. Predictive modeling was also performed for biaxial braids based on the packing density in the material and parameters of the braiding process. The good conformance of the predictive models gives a validated starting point for development of braided structures concerning stiffness behavior. In addition, the information about the fiber architecture can be used for failure analysis on unit cell level.

Comparing the fracture toughness of 3-D braided preform composites with z-fiber-reinforced laminar composites

Organic polymer engineering composite materials based on layered fabrics have many advantageous properties and processing features. However, performance properties of the layered OPECs, especially impact strength, delamination resistance, and fracture toughness are poor. Three-dimensional preforms fabricated with 3-D weaving, knitting and braiding techniques, are employed to improve the shortcomings of 2-D layered fabric reinforcements. z-directional microfiber-reinforced laminar composites were recently developed to improve impact strength and fracture toughness without reducing in-plane performance properties at minimal added cost and at higher productivity in the Flock Materials Laboratory at the University of Massachusetts Dartmouth. The effectiveness of laminar composite z-directional microfiber reinforcement (by a flocking process) in improving fracture toughness was compared with that of a 3-D braided 8-layer glass fiber preform/epoxy composite plate. The results show that the Mode I fracture toughness (GI) of the 3-D braided preform reinforced composites are about 10 times of the 2-D layered glass fabric laminar composites (control) as expected. This is comparable to the results of z-directional microfiber-reinforced composites; up to 9 times increase in GI over that of 2-D glass fabric/epoxy laminar composite (control). The presence of through-thickness microfiber (flock fiber) reinforcements in the matrix resin between reinforcement layers is found not to reduce the in-plane mechanical properties; the fracture toughness however, increases significantly.

Tribological Performance of 3D Braided Glass Fibers Reinforced Light-curing Dimethacrylate Resin Composites

3D braided glass fiber reinforced visible-light-cured resin composites (denoted as G3D/EEPE) were prepared by impregnation plus light-cured technique, and their tribological properties were studied in this work. It was found that the coefficient of friction and the specific wear rate of the G3D/EEPE composites decreased with increasing Vf. Beyond a Vf of 32%, however, a slight increase in the specific wear rate of the G3D/EEPE composites was found. The decreased friction coefficient and increased specific wear rate were observed in the G 3D/EEPE composites with increasing normal load regardless of velocity. The silane coupling treatment effectively improved the wear resistance of the G3D/EEPE composites. Though the G3D/EEPE composites showed lower friction coefficient and specific wear rate at lubricated condition than at dry contact, the similar adhesive wear mechanism was observed under two conditions.

Fabrication and Characterization of High-density Polyethylene - Coconut Coir Composites with Stearic Acid as Compatibilizer

Composites of high-density polyethylene (HDPE) with coconut coir as the fiber and stearic acid (SA) as the coupling agent were fabricated by compression molding. Coconut coir in the form of braided fibers and whiskers were used for the study. Incorporation of the coir, buckled the composites and decreased their tensile strength and elongation at break. The extent of buckling and deterioration in the mechanical properties was proportional to the amount of coir loaded as filler. Treatment of the coir with SA as the coupling agent enhanced the mechanical properties and the thermal stability of the composites. It also reduced the extent of buckling and prevented aging of the composites to certain extent in aqueous and strong acidic and alkaline media. Scanning electron micrographs of the fractured samples showed improved adhesion between coir and HDPE matrix upon treatment with SA.

Indirect measurement of tensile strength of hollow fiber braid membranes

In order to estimate the tensile strength (σ β) of hollow fiber braid membrane, two linear equations relating interfacial shear strength (τ) and σ β were formulated. The first involves a simple τ equation and the second includes an intercept value that represents the maximum load for σ β. The two equations were confirmed experimentally by three sets of tests. The experimental data were analyzed with linear plots to indirectly calculate σ β of the coated layer. All the experimental results of both σ β and τ showed good agreements with the calculated values. It is noted the test methods and the corresponding theories are quite reliable to test the hollow fiber braid membranes. Other factors such as membrane structures, pore size and thickness were also correlated to tensile strengths of different samples. The method developed is very simple and handy in terms of providing comparable data information which is useful when choosing appropriate membrane products for various applications.

Stress Relaxation and Creep: Viscoelastic Properties of Common Suture Materials Used for Flexor Tendon Repair

The time-dependent mechanical behavior of common suture materials may have a pronounced influence on the quality of flexor tendon repairs with respect to gap formation. Sutures commonly used in plastic surgery, particularly for hand tendon repair, were tested in tension for analysis of stress relaxation and creep properties. The three materials tested were (1) Prolene, a monofilament polypropylene(Ethicon, Somerville, NJ); (2) Ethilon, a monofilament nylon(Ethicon, Somerville, NJ); and (3) Ticron, a braided polyester fiber (Sherwood, Davis & Geck, St. Louis, MO). All measurements were made with 1.5-mm (4-0) varieties of the sutures, in physiological buffered solution (0.9% phosphate-buffered saline [PBS]) at both room (22 degrees C) and body temperature (37 degrees C) conditions. Ticron was the stiffest suture at both room and body temperature, followed by Prolene and Ethilon. Both Prolene and Ethilon showed statistically (p< .05) reduced stiffness at body temperature. Prolene exhibited statistically larger (p< .05) relaxation and creep ratios than the other two sutures, and it was the only material to show temperature effects in creep and relaxation. Based on static and viscoelastic mechanical properties, Ticron is the most suitable suture for flexor tendon repairs when compared to Prolene and Ethilon.