Fabric Tube Research Articles

Design and structural analysis of an inflatable coated fabric manipulation arm

This paper presents the structural behaviour of a novel inflatable manipulation arm, which consists of inflatable coated fabric tubes and bellows-type joints. In order to minimise the actuation moment, a rotational joint with creases, analogous to a spacesuit elbow, has been introduced. The biaxial tensile and shear tests have been carried out to evaluate the elastic constants of the PVC-coated polyester fabric membranes of the inflatable arm. Finite element analysis has been carried out to predict the mechanical behaviour of the inflated arm structure. Effects of the internal pressure on the arm deflection, and influence of crease geometric parameters, e.g. number, width and depth on the rotation performance are evaluated. A prototype of the inflatable arm has been developed to perform an experimental investigation on its rotational behaviour. Good correlations have been found between the predictions and the experimental results. The current work on a representative single-joint inflatable arm unit provides the rationale and knowledge to develop long range multi-joint manipulators.

Unit cell modeling on torsion damage behavior of a novel three-dimensional integrated multilayer fabric-reinforced composite tubular structure

Torsion damage behaviors of composite tubes are key factors in the design of tube structures, such as transmission shafts. During service, torsion in the transmission shaft induces delamination damage. A novel three-dimensional fully integrated multilayer tubular fabric aimed to eliminate delamination was invented by authors. This fabric is in tubular form with several layers of crimp-free in-layer yarns oriented at prescribed orientations and fully interlocked by a set of through-layer yarns, which are often made of the same type of fibers as the in-layer yarns. We investigated torsion damage behaviors of the integrated fabric-reinforced composite tubes. The torque–torsion angle curves were obtained and the torsion damages were phenomenologically analyzed. A unit cell model of the integrated fabric composite circular tube was established to numerically reveal the torsion damage mechanisms. For optimizing the torsion behaviors, the axial yarns should have high stiffness and the binder yarn should have high strength. More specifically, the axial yarn should use carbon fiber tows, and high-strength polymer fiber tows could be used for the binder yarns.

Monitoring of physically restored seagrass meadows reveals a slow rate of recovery for Thalassia testudinum

Physical damage by motor vessels is a widespread problem for seagrass meadows, with hull and propeller strikes accounting for thousands of acres of impaired habitat in Florida, United States, alone. Because the excavations can become topographically unstable, and because recolonization and succession of seagrasses can require decades to reach climax, Thalassia testudinum‐dominated communities, there has been increasing efforts to regrade and stabilize impacted sediments, and to speed succession. A prior project involving eight vessel groundings in two hydrodynamic settings (high and low energy) examined the relative efficacy of capping injuries with sand‐filled fabric tubes or limestone pea rock, followed by planting of fast‐growing seagrass species and nutrient amendment using bird‐roosting stake deployments. Monitoring after 4 years showed recruitment of fast‐growing, subordinate species: Syringodium filiforme or Halodule wrightii, particularly in low‐energy environments; however, T. testudinum had not yet returned to natural densities. The current study extended monitoring an additional 3 years. At 7 years posteffort, T. testudinum recolonization was still incomplete. Of the eight sites, only three had statistically recovered. In low‐energy areas, H. wrightii cover was greater than in reference meadows, and a strong inverse relationship between H. wrightii and T. testudinum was observed. One explanation is that residual nutrients from bird feces switched the competitive outcome. We demonstrate using seagrass tissue N:P that nutrients delivered via bird stakes remained in the sediments of low‐energy environments, and argue that prolonged fertilization resulted in competitive advantages for H. wrightii, depressing T. testudinum recruitment and delaying recovery of the targeted seagrass community.

A novel evaporative cooling tower constructed from an inflatable fabric duct

This paper describes a prototype of a novel vertical cooling tower constructed from an inflatable fabric duct that incorporated a water spray nozzle mounted at the top. The device was constructed using two concentric impermeable fabric tubes sealed at either end. It was inflated using a small pressurization fan located at the tower base. A numerical performance model was developed to estimate the downstream conditions of the evaporative cooling tower, and the length necessary for complete evaporation. To test the predictive capability the model of the evaporative cooling tower, experiments were performed under different ambient conditions. The prototype tower did exhibit downdraft cooling. However, the ambient conditions under which the validation measurements were performed were not conducive to achieving a moist air flow that could be measured accurately, and further investigation is recommended.

Designing of advanced smart medical stocking using stress-memory polymeric filaments for pressure control and massaging

Compression treatment for the patients with chronic disorders such as venous ulcers and varicose veins needs the proper and adequate level of pressure sustainability. This has been a great challenge for health practitioners and stocking manufacturers even till today. There is an imperious need of any research, where internal compression pressure can be controlled or readjusted externally. In line with this, for the first time this study is focused mainly to design and optimize the smart stocking structure by integrating the stress-memory polymeric filament as a main load bearing element. Six different structures were employed to prepare the stocking fabric tubes. All the structures were investigated for pressure analysis and studied the effect of physical parameters such as temperature, strain, and leg radius. It is possible to control the level of massage effect by varying the stocking structures. An empirical relationship is derived, which provides the knowledge for how to control the stocking pressure with structural modifications like never done before. The effect of massage function on blood flow velocity in the popliteal vein on lower limb was objectively measured by Doppler ultrasound scanning. This study also sheds the insight of stocking structural modification for pressure control and provide the benchmark for achieving the efficient compression. This advanced stress-memory polymeric filaments based multifunctional compression stocking provides static pressure, massage effect, and easy size fitting in a more controlled manner for smart compression therapy.

PENGEMBANGAN KAIN TENUN CEPUK SEBAGAI BAGIAN PARIWISATA BUDAYA BERKELANJUTAN DI NUSA PENIDA

Bali has a variety of tourism potentials including cultural tourism either in the form of products or exotic craft. One fairly well-known cultural productis woven fabrics (Kain Tenun), such as Kain Tenun Cepuk that exist in the area of Nusa Penida. The existence and uniqueness of the woven fabric is expected to help increasing tourism in the island, as well as increasing the income of both Bali tourism sector or specifically the people of Nusa Penida. Thus the present study was made to assess the potential Woven fabric tube Tanglad, Nusa Penida, as well as determine strategies and programs that can be done to develop the potential of the woven fabric tube Tanglad as a means of developing cultural tourism. This study is using a qualitative descriptive approach to measure the variables involved, and SWOT matric to explain and define the data in the formulation of strategies and programs. The data obtained several factors that determine the potential development of the Kain Tenun Cepuk, which is categorize as internal and external factors, in which successfully formulated four strategiesand programsthat can be developed, covering SO strategies (developingKain Tenun Cepuk and the surrounding areas), ST (developing cultural tourism in Tanglad and Nusa Penida), WO (dealing with right promotion issue), and WT (related to human resource development). The research is expected to be referencedto number of policies that can be taken by local government to develop tourism in Tanglad, Nusa Penida, as well as for the community to be able to develop the potential of the Kain Tenun Cepuk better.

Prediction of Pressure due to Elastic Fabric Tube Following Energy Principle

Prediction of Pressure due to Elastic Fabric Tube Following Energy Principle

Influence of linear density of elastic inlay yarn on pressure generation on human body

Pressure garments are used to heal different medical conditions such as hypertrophic scars, venous problems and orthopaedic disorders. The requirement of therapeutic pressure for different applications is different. So there is a need for engineering pressure garments according to the requirement. Pressure garments are made from elastic knitted fabric. The principle of pressure generation depicts that the tensile property of the elastic knitted fabric is an important factor which can be regulated by varying the property of elastic inlay yarn used in the fabric. Little information is available in this aspect. In the present study, elastic knitted fabric tubes were prepared by varying the linear density of the elastic inlay yarn. Pressure exerted by the fabric tubes was studied on 10 male and 10 female upper arm of left hands. The pressure generation behaviour was then compared in between male and female subjects. The results were also compared with pressure development on rigid body. Results showed that tensile property of elastic knitted fabric can be regulated by varying the linear density of elastic inlay yarn. Pressure exerted by the fabric tubes can be regulated by changing the linear density of elastic inlay yarn. Pressure generation was always higher on rigid body than human body.

Controlled and Sequential Delivery of Fluorophores from 3D Printed Alginate-PLGA Tubes.

Controlled drug delivery systems, that include sequential and/or sustained drug delivery, have been utilized to enhance the therapeutic effects of many current drugs by effectively delivering drugs in a time-dependent and repeatable manner. In this study, with the aid of 3D printing technology, a novel drug delivery device was fabricated and tested to evaluate sequential delivery functionality. With an alginate shell and a poly(lactic-co-glycolic acid) (PLGA) core, the fabricated tubes displayed sequential release of distinct fluorescent dyes and showed no cytotoxicity when incubated with the human embryonic kidney (HEK293) cell line or bone marrow stromal stem cells (BMSC). The controlled differential release of drugs or proteins through such a delivery system has the potential to be used in a wide variety of biomedical applications from treating cancer to regenerative medicine.

An analysis of tube drawing process used to produce squared sections from round tubes through FE simulation and response surface methodology

Tube drawing process is an attractive manufacturing technique in automobile, medical, and aerospace industries. The quality of fabricated tubes is highly affected by drawing parameters, e.g., die geometry, material properties, friction conditions, and drawing ratio. In the present study, an extensive attempt has been made to find optimal combinations of drawing parameters, i.e., die angle, friction coefficient, tube entrance velocity, and deformation length regarding minimum drawing force and dimensional error as well as maximum linear and peripheral thickness distributions. A combination of finite element model, validated through trial experiments, and face-centered central composite design was used to design a matrix. Then, response surface methodology (RSM) was used to correlate empirical relationships between process factors and responses. The developed RSM models were then used to find the effects of tube drawing parameters on the mentioned performances. RSM was used further for the selection of optimum process parameters to achieve the desired quality regarding tube drawing performance in producing squared sections from round tubes. The results showed that to attain desired quality characteristics, the die angle of 7.5°, deformation length of 3 mm, friction coefficient of 0.3, and entrance velocity of 5 mm/min should be selected. A comparison between the optimal results and those derived from finite element (FE) model showed that the proposed approach would be able to predict optimal drawing process combinations with a high degree of accuracy.

Biocompatibility and Systemic Safety of a Novel Implantable Annuloplasty Ring for the Treatment of Mitral Regurgitation in a Minipig Model.

Prosthetic annuloplasty rings are a common treatment modality for mitral regurgitation, and recently, percutaneous implantation techniques have gained popularity due to their favorable safety profile. Although in common use, biocompatibility of annuloplasty rings has been reported only sparsely in the literature, and none of these reports used the percutaneous technique of implantation. We report on the biocompatibility and the systemic safety of a novel transcatheter mitral valve annuloplasty ring (AMEND™) in 6 minipigs. This device is composed of a nitinol tube surrounded by a braided polyethylene terephthalate fabric tube. The device produced no adverse inflammatory response, showing gradual integration between the metal ring and the fabric by normal host fibrocellular response, leading to complete neoendocardium coverage. There was no evidence for adverse reactions, rejection, or intolerance in the valvular structure. In 2 animals, hemopericardium resulted from the implantation procedure, leading to right-sided cardiac insufficiency with pulmonary edema and liver congestion. The findings reported herein can serve as a case study for the expected healing pathology reactions after implantation of transcatheter mitral valve annuloplasty rings.

Self-healing of low-velocity impact and mode-I delamination damage in polymer composites via microchannels

Microchannels embedded polymer composites were fabricated by resin infusion process using carbon fabric, epoxy resin and hollow glass tubes (HGTs). The effect of a range of low-velocity impact (LVI) and mode-I delamination (M1D) damage on the flexural strength of microchanneled carbon- epoxy composites was studied. A self-healing approach was also employed to recover their lost flexural strength due to these damages. Moreover, influence of LVI, M1D damage and healing on the failure behavior of microchanneled carbon- epoxy composites was also investigated. The results of flex- ural after impact (FAI) and flexural after delamination (FAD) showed that LVI has more deleterious effect on the flexural strength of carbon- epoxy composites than M1D damage. The loss in flexural strength increased linearly with increase in both impact (by higher impact energies) and delamination damage (by longer delamination lengths). Scanning electron microscopic (SEM) study revealed that self-healing agent (SHA), stored in HGTs placed within carbon- epoxy composites, effectively healed both LVI and M1D damage with excellent healing efficiencies.

Scalable self‐assembly process for the fabrication of sub‐millimetre three‐dimensional cylindrical tubes

The analysis, simulation and experimental fabrication of three-dimensional (3D) cylindrical tubes formed from 2D aluminium/silicon dioxide (Al/SiO2) substrates are presented. The photolithographically fabricated planar Al/SiO2 substrates bend under residual mechanical stress after release, self-assembling into 3D cylindrical tubes. They present an analytical model that allows them to reliably predict the resulting radius of curvature of bi-layer Al/SiO2 tubes with uniform cross-sections, and provides an approximate solution for SiO2 substrates with patterned Al cross-sections. Finite element analysis simulations and measurements of fabricated tubes show agreement with the model. In addition, they show through a series of batch experiments that the self-assembly process is repeatable with proper design of the substrates.

Experimental Determination of Inflatable, Braided Tube Constitutive Properties

AbstractThe primary objective of this study was to conduct constitutive tests of relatively large diameter inflatable, braided fabric tubes at different inflation pressures and braid angles in order to quantify the longitudinal modulus, in‐plane shear modulus and effective lamina stiffness properties. The stiffness properties quantified here are of high interest because the same braided fabric tubes have been used in the construction of test articles for a major, multi‐year, ground based test campaign led by the United States National Aeronautics and Space Administration. These properties are also input directly into high‐fidelity yet computationally intensive 3D shell‐based finite‐element simulations of the large, inflatable structures. Experimental methods employed during this study included tension–torsion testing, uniaxial tension testing of individual fibre tows, and uniaxial tension testing of gas bladder coupons. Digital image correlation was used to measure all of the geometric information that is necessary to perform netting theory calculations. The test results indicate that fabric in‐plane shear modulus is highly dependent on both braid angle and inflation pressure, but that longitudinal stiffness is quite small and relatively unaffected by braid angle and pressure. In addition to advancing the state‐of‐the art in experimental constitutive property determination of inflatable, braided fabric, this study includes the development of a method to back calculate lamina properties from the experimental results that are suitable for use as input to commonly used finite‐element programmes. The digital image correlation data revealed spatial variation of shear strain that was important to consider when computing the gross shear stiffness. Digital image correlation data also captured the braid surface flattening with increasing inflation pressure, which supports the fibre de‐crimping theory.

Multibranched hybrid device for frozen elephant trunk: What does it change?

Multibranched hybrid device for frozen elephant trunk: What does it change?

Compatibility of Polyvinylidene Difluorid/Polyurethane and Preparation of Composite Tubular Membrane

The compatibility of polyvinylidene difluorid (PVDF) and polyurethane (PU), the thermodynamics of the PVDF/PU/DMF (N-N-Dimethylformamide) membrane-forming systems were studied, and the composite tubular membranes of PVDF/PU-PET knitted fabric tube were prepared by the immersion precipitation phase inversion method. The results showed that the PVDF/PU system was partly compatible by the measurements of the solubility parameter theory, the mixing enthalpy, the viscosity. With PU content increasing, the gelation values increased and the instantaneous liquid-liquid phase separation was preferred to occur. The water flux of the composite tubular membranes were enhanced from 1264.81 to 2165.35 L/m2.h with PU content increasing from 10wt% to 40wt%, which resulted from the an increment of the membrane porosity and the improvement of the hydrophilicity.

Effect of linear density of inlay yarns on the structural characteristics of knitted fabric tube and pressure generation on cylinder

Knitted fabrics containing elastic inlay yarns are used extensively for the production of pressure garments (PG). An understanding of the relationship between the fabric-garment-body parameters, which affects the resultant pressure generated on a body, is critical to the design and engineering of PG. In the present study, fabrics containing elastic yarns of varying linear densities have been compared on the basis of pressure generated by them on rigid cylinders of different curvatures. Effect of fit (i.e. reduction factor [RF]) has also been assessed. It was found that with increase in linear density of inlay yarn, the knitted loops become wider and shorter in height. Fabric thickness and weight both increase. Analysis of variance shows that the linear density of the inlay yarn is the most significant factor, followed by RF and curvature. Effect of body curvature was found to be minimal. For achieving very high (≤35 mm Hg) and low(≤20 mm Hg) pressures, one has to go for heavy or low linear density of inlay yarns. However, for intermediate pressure (20–30 mm Hg), the choice for linear density of inlay yarn and reduction factor is wide.

Flared textile cuff to be apposed on the proximal sealing zone in fenestrated stent-grafts

Current customized fenestrated devices require a fabrication delay of 4–6 weeks and therefore cannot be considered for the treatment of emergent or urgent aortic pathology. A flared textile cuff capable of better sealing the connection between a stent-graft fenestration and a branching stent-graft could bring more flexibility in treating patients with peri- and juxta-renal abdominal aortic aneurysms. Four different flared textile cuff prototypes were fabricated by compression molding of woven fabrics having structure similar to those of commercially available devices. Each cuff comprised a flat collar as a base, an arc as a curved section, and a top as a regular fabric tube. The fabric count, density, and thickness decreased from the first to the third sections and the results differed according to the structure. The physical and mechanical properties of these flared fabric cuffs were similar to those found in commercially available stent-grafts. The flared textile cuffs showed a scope of properties adapted for easier delivery and are acceptable to various sizes and shapes of fenestration. The development of flared textile cuffs represents a considerable advancement in endovascular therapy: (1) allowing a fenestrated solution to be readily available off-the-shelf; (2) providing an adequate seal of the ancillary stent-graft to the main body of the stent-graft.

Fatigue and/or Failure Phenomena Observed in the Fabric of Stent-Grafts Explanted After Adverse Events

In this study, we aimed to investigate changes to the fabric of Talent stent-grafts following implantation of aortic endografts and to determine the possible causes of fatigue and/or failure of the grafts. Six devices were explanted at reoperation (N=5) and autopsy (N=1). Selected segments were assessed nondestructively by gross observation and destructively by analyzing textile characteristics and chemical properties. All of the devices showed a 4/4 twill woven fabric of monofilament polyester. These devices, explanted at reoperation and autopsy, presented different levels of fatigue and/or failure. Numerous holes were found in the fabric of two devices. The minor damage caused by the passage of the sutures through the weave to fasten the Nitinol wires did not progress significantly over time. The sutures remained relatively intact, except for some distortions. The main failure mode was the abrasion of the yarns at the apices of adjacent Nitinol stents. In two devices, this abrasion resulted in fraying of the yarns and holes in the fabric tubes. This short series of explanted devices provides evidence of damage to polyester fabric used in aortic endografts and raises questions regarding their resistance to abrasion and the risk of endoleak associated with monofilament fabric yarn.

A polylactic acid non-woven nerve conduit for facial nerve regeneration in rats

This study developed a biodegradable nerve conduit with PLA non-woven fabric and evaluated its nerve regeneration-promoting effect. The buccal branch of the facial nerve of 8 week-old Lewis rats was exposed, and a 7 mm nerve defect was created. A nerve conduit made of either PLA non-woven fabric (mean fibre diameter 460 nm), or silicone tube filled with type I collagen gel, or an autologous nerve, was implanted into the nerve defect, and their nerve regenerative abilities were evaluated 13 weeks after the surgery. The number of myelinated neural fibres in the middle portion of the regenerated nerve was the highest for PLA tubes (mean ± SD, 5051 ± 2335), followed by autologous nerves (4233 ± 590) and silicone tubes (1604 ± 148). Axon diameter was significantly greater in the PLA tube group (5.17 ± 1.69 µm) than in the silicone tube group (4.25 ± 1.60 µm) and no significant difference was found between the PLA tube and autograft (5.53 ± 1.93 µm) groups. Myelin thickness was greatest for the autograft group (0.65 ± 0.24 µm), followed by the PLA tube (0.54 ± 0.18 µm) and silicone tube (0.38 ± 0.12 µm) groups, showing significant differences among the three groups. The PLA non-woven fabric tube, composed of randomly-connected PLA fibres, is porous and has a number of advantages, such as sufficient strength to maintain luminal structure. The tube has demonstrated a comparable ability to induce peripheral nerve regeneration following autologous nerve transplantation.