Fiber Belt Research Articles

Bending behaviors and toughening mechanism of carbon fiber-aluminum honeycomb sandwich structures with stitched fiber belts

Bending behaviors of carbon fiber-aluminum honeycomb sandwich structures, that are toughened by stitched fiber belts, are experimentally and numerically studied. It is found that the stitched fiber belts show potential to enhance the peak load of sandwich specimens by up to 44.3%, and to arrest interfacial crack growth. Firstly, FE models are proposed for the sandwich structures with stitched carbon fiber belts, and the FE models are verified by three-point bending tests. Secondly, the effects of stitched carbon fiber belts on bending behaviors of sandwich beam are studied. Combining the experimental and numerical results, the main toughening mechanism of stitched fiber belts is observed. The stitched fiber belts increase bonding area between face-sheets and honeycomb core, on one hand, and therefore enhance the interfacial strength. On the other hand, the angled fiber belts inside the core are found to enhance load bearing capacity and transverse shear stiffness.

Numerical and experimental investigation for flexural response of Kevlar short fiber tissue/carbon fiber belts toughened honeycomb sandwich plate

This paper investigates the flexural behavior of honeycomb sandwich panels with a toughened/untoughened interface using carbon fiber belt and short aramid fiber tissues. In the first part of the paper, bending response analysis of carbon fiber aluminum honeycomb sandwich plates with an untoughened interface is done using finite element-based first-order shear deformation theory. In the second part, experimental analysis is done to examine the effect of loading rates on the mechanical characteristics of plain and toughened sandwich panels using a three-point bending test. Four types of interface toughening are used as unidirectional and bi-directional stitches of carbon fiber belts, Kevlar short-fiber tissues, and carbon fiber belts combined with Kevlar short-fiber tissues. Experimental result shows that interface toughening improves the maximum load and energy absorbed by sandwich specimens for all loading rates. A scanning electron microscope is used to observe and analyze the failure mode and mechanism of strengthening the interface. It is observed that the stitch of the carbon fiber belt increases the adhesion contact between face sheets and core leading to prevent interfacial debonding. The peak load and energy absorptions of carbon fiber belts toughened interface sandwich are increased by 51 % and 42.5 %, respectively, compared with that of the plain sandwich by a small increment of weight (14%).

SLIP HANDLING ON CONVEYORS TO EXTEND THE LIFE OF CONVEYORS AT THE DEPARTURES TERMINAL

The departure terminal’s Abdulrachman Saleh Malang Airport has facilities as an improvement in services for airplane passengers, such as aviobridges, escalators, travelators, elevators, and conveyors. Conveyors are mechanical systems that transfer luggage considerably from one location to another. To facilitate routing procedures, an effective model for conveyor operations must be developed, as well as the maintenance operation. This study aims to determine the consequences of lack of maintenance on the conveyor belt, namely the occurrence of slack in the belt so that it continues to experience abrasions on the sides of the conveyor and tears on the edges of the belt. The tear causes the fibers to unravel so that slip occurs between the belt and the upper idler shaft (carry idler) so that the idler cannot rotate. This causes the conveyor belt to run and malfunction. This research uses a qualitative method of conducting an exploratory study of the conveyor belt using experimental description research by describing and analyzing the existing conditions on the conveyor. The result is that there are belt fibers that cause slippage on the conveyor. Handling that can be done is cutting the fiber belt. The conclusion is that many factors can cause slippage on the conveyor belt, such as too heavy a load, old belt age, and the distance between the collecting belt conveyor and the transfer line conveyor. Maintenance can be done on the equipment to avoid slippage on the conveyor. Conveyor maintenance activities consist of two types, namely unplanned maintenance and planned maintenance. Unplanned maintenance is also called reactive maintenance or emergency maintenance.

Three-point bending properties of carbon fiber/honeycomb sandwich panels with short-fiber tissue and carbon-fiber belt interfacial toughening at different loading rate

The bending performances at different loading rate are studied for carbon fiber/honeycomb sandwich panels toughened by short aramid fiber tissues and carbon fiber belts. The carbon fiber belts are stitched cross the pores of honeycomb core for interfacial improvements. Three-point bending tests at different loading rates are carried out to investigate the effect of short aramid fiber tissue and carbon fiber belt on mechanical properties of carbon fiber/honeycomb sandwich specimens. Experimental results firstly indicate that the short-aramid-fiber interfacial toughening and carbon fiber belts toughening could both enhance the energy absorption and peak load of sandwich specimens at loading rates ranging from 2 mm/min to 500 mm/min. The failure modes and microstructures of toughened specimens are observed to analyse and explain the underlying mechanism of enhancing effect. It is illustrated that crack isolation phenomenon is found to be the main mechanism for avoiding interfacial damage of the sandwich specimen.

Pressure Capacity Study of Φ100 Reinforced Thermoplastic Pipe

The pressure capacity of reinforced thermoplastic pipe was studied by the finite element analysis and experimental study using Φ100 reinforced thermoplastic pipes. The simulation results illustrated that the failure mode of reinforced thermoplastic pipe under internal pressure was the break of glass fiber belt in structural layer. Moreover, the simulated burst pressure fitted well with the experimental result, the small deviation between two results may be resulted from the process defects of RTP.

Sisal fiber reinforced high density polyethylene pre-preg for potential application in filament winding

A thermoplastic-penetrated natural fiber belt was developed for potential application in filament winding. Discontinuous sisal fiber bundles were impregnated with high density polyethylene and then connected into continuous pre-pregs via hot-pressing. The interfacial bonding was improved by treating the fibers with sodium hydroxide (NaOH) and three types of coupling agents (NH2C3H6Si(OC2H5)3, C2H3Si(OC2H5)3 and C51H112O22P6Ti). Tensile properties of the fiber bundles, pre-pregs, and annular specimens were determined. The fiber surface microstructure and the pre-preg interfacial bonding were evaluated via scanning electron microscopy and Fourier transform infrared spectroscopy. Among the four treatments, 2% C2H3Si(OC2H5)3 yielded the most significant improvement in the tensile properties of the pre-pregs and annular specimens. The fiber bundle was less damaged by the coupling agents treatment comparing to NaOH treatment. When the overlap at the end of the sisal fibers was >11 mm, the presence of the joint had no effect on the tensile strength of the pre-preg. The pre-preg belt containing treated fibers, which was evaluated based on the requirements of filament winding applications, exhibited a high performance.

Dynamic collapse test on eccentric reinforced concrete structures with and without seismic retrofit

Reconnaissance reports on structures damaged or collapsed by severe earthquakes have revealed several common characteristics in their structural members and systems, such as insufficient reinforcement details in beam-column joints and transverse confinements, low aspect ratios, soft and or weak stories, and eccentric plans. Dynamic tests were carried out to investigate the collapse process of reinforced concrete structures that had seismically deficient reinforcement details (light transverse reinforcement) and seismic systems (soft/weak stories and eccentric plans). A comparison of collapse behaviors with and without seismic retrofits also verified the effectiveness of the SRF (super reinforced with flexibility) strengthening method, which was developed to prevent the loss of axial load carrying capacity even at excessive lateral deformation. The columns of one specimen were strengthened with polyester fiber belts and its shear walls with polyester fiber sheets, while the members of the other were not. Each specimen was designed following old (1970s) reinforcement detail practice in Japan, and is a one-third-scale reinforced concrete structure with considerable stiffness and strength eccentricity in the first story. The specimens were composed of independent column frame and shear wall frame. Torsional response resulting from the eccentricity in the 1st story induced a displacement concentration on the weak frame, and eventually the independent columns of the RC specimen failed in shear and lost their axial load carrying capacity. On the other hand, the SRF specimen survived not only an identical earthquake load to the one that caused the RC specimen to fail, but also three additional earthquake loads, although significant strength deterioration and considerable lateral and vertical deformation were generated at the end of the test. The following conclusions were drawn from the comparison of the two specimens’ responses: axial column collapse cannot be predicted from vertical responses since the vertical behavior of bare RC columns was not discernibly different from that of SRF columns until axial collapse was initiated, and the SRF strengthening method is effective in confining the column and preventing the cracking progress, thus modifying the failure mode of the RC columns from brittle shear failure after flexural yield to flexural dominant behavior.

Experimental Investigation on Shear Property of RC Beams with Aramid Fiber Mesh Stirrups

This paper develops a new-typed high-durability RC structures in which the steel stirrups are replaced by mesh stirrups weaved with soft high performance fiber belt. The experiments are carried out to investigate the shear property of six beams with soft aramid fiber mesh stirrups and one common RC beam and the results show that the failure state in the slope sections of the RC beams with fiber belt mesh stirrups is similar to the common RC beam. It was also found the shear property of beams with lean fiber mesh stirrups is better than that with vertical and horizontal mesh stirrups, and with the high-elastic- modulus fiber stirrups better than the low-elastic-modulus’s. In addition, the distributions of fiber stirrups strain at slope section are also observed. Based the experimental results, a model for beams with fiber mesh stirrups was established and the formula of shear bearing capacity was suggested.

COMPRESSIVE BEHAVIOR OF RC COLUMN CONFINED EXTERNALLY BY ARAMID FIBER BELT PRESTRESSING

The seismic retrofit concept of using aramid fiber belt with initial lateral prestressing for RC columns was proposed by one of the authors. An important point of this technique is that the lateral prestressing can be initially introduced into column through aramid fiber belts using couplers and thus the benefits of active confinement as well as passive confinement can be captured. To analyze the nonlinear behavior of RC columns retrofitted by the proposed technique, the appropriate constitutive law of confined concrete is essential. Therefore, to establish the constitutive law of confined concrete, axial compression tests of RC columns externally confined by aramid fiber belt prestressing were conducted. The stress- strain relationships of concrete and aramid fiber belts are obtained through the experimental investigation. Finally, an appropriate constitutive law of confined concrete for the mensioned retrofit technique is proposed.

Project artificial myocardium

Where is a place to be assisted for the patients with congestive heart failure? It is contraction of myocardium. We do not need to exchange the whole hearts. We started the ARTIFICIAL MYOCARDIUM development project. In the first step, pneumatic drive type artificial myocardium was developed. Next, development of an implantable type device was started. The animal experiment which studies the direct ventricle supporting effect by this motor was conducted. Although cardiac assistance of the right ventricle was enough as a result of repeating an animal experiment, the left ventricle supporting effect was inadequate. By such reason, we planned the development of an electrohydraulic driving system with grass fiber belt for fixation. The drive system with which it equipped between ribs controls silicon oil in our plan. Energy is supplied by transcutaneous energy transmission system from the outside of the body. As the results, this device is easily attached to the ventricle and the left ventricle and the right ventricle were able to be assisted as a result of the animal experiment. The cardiac output increased and blood pressure rose in the time series data during artificial myocardium support. Since this device is not a pump, it does not have a valve and does not have the risk of a thrombus, either. Therefore, it is also possible to implant in prevention to a slight heart failure patient. It is expected that it becomes an important artificial organ with a big market.

Emergency Retrofit of Shear Damaged Extremely Short RC Columns Using Pre-tensioned Aramid Fiber Belts

The seismic retrofit of existing RC buildings, which are vulnerable to seismic excitation, remains an active area of research. Emergency retrofit is necessary for rehabilitation of damaged RC buildings immediately after earthquake occurrences. The emergency retrofit technique is a laborsaving, quick and dry process. From such viewpoints, an emergency retrofit of RC columns damaged in earthquakes is proposed in this study. The pre-tensioned aramid fiber belt acts as a shear strengthening element as well as an axial capacity recovery method since the belt provides transverse confinement for the column. The retrofit method sufficiently recovers the earthquake performance as long as the damage caused by the earthquake is within the moderate level and the column can sustain the vertical load.

体表面長さ変化を利用した介護者腰部負担軽減衣服

Body care motions apply a large amount of stress on caregivers’ muscles and spines, so most of them suffer from low back pain. One of the major factors of low back pain is the low back muscular load to keep the deep flexion posture. This study concerned development of a suit-type back muscle supporter named “the care suit,” which reduces low back load.Elastic fiber belts (support lines) are arranged on the back and leg parts of the suit. The support lines are relaxed so as not to interfere with daily trunk motion, arm motion, walking, and sitting motion, but to exert tensile force and extension moment in the deep flexion posture. The care suit is a two-piece design to improve comfort and convenience.To optimize the layout of the support lines we developed a small reel-type device to measure body surface deformation. As the result of measurement by this device and a system for posture measurement during several motions, the back support lines are arranged in an x-shape from the side neck point to the point internally dividing the Jacoby-line at a ratio of 1 to 2. The leg support lines branch at the rear face of the thigh and are attached to the apex of the patella. The maximum tension of support lines is limited by the user’s shoulder pain to 140 N for males and 85 N for females.The effect of the care suit was evaluated by electromyograms of back muscles. The action potential in the deep flexion posture was 25% decreased. In comparison with the conventional corset, the effect of the care suit for back muscle was equal, but the care suit is superior in that it does not interfere with flexion motion.The lumbar joint muscular moment during a diaper change operation was calculated from body posture through a rigid body link model. The results of this calculation showed that the stored load during the operation was decreased by 30% by the care suit. Furthermore the summation of intervertebral disk compressive force was reduced by 15% during the operation. Therefore the care suit is effective for reduction of not only continuous muscular load but also spinal load. Practical use by caregivers also resulted in good evaluations as it reduced continuous muscle load for a diaper change operation, bed making operation, etc.Conclusively, the low back load during body care motions can be reduced by the care suit developed in this research. This care suit is under patent application.

The balloon-borne electron telescope with scintillating fibers (BETS)

We describe a new detector system developed for high-altitude balloon flights to observe the cosmic-ray electrons above 10 GeV. The Balloon borne Electron Telescope with Scintillating (BETS) fibers instrument is an imaging calorimeter which is capable of selecting electrons against the large background of protons. The calorimeter is composed of a sandwich of scintillating optical-fiber belts and lead plates with a combination of three plastic scintillators for shower trigger. The total thickness of lead is 40 mm (∼ 7.1 r.l.) and the number of fiber belts is nine. In each belt, alternating layers are oriented in orthogonal ( x and y) directions. Two sets of an intensified CCD camera are adopted for read-out of the scintillating fibers in the x and y direction, respectively. The accelerator beam tests were carried out to study the performance of detector for electrons in 1996 and for protons in 1997 at CERN-SPS. The instrument was successfully flown aboard high-altitude balloon in 1997 and 1998. It is demonstrated by the flight data that a reliable identification of the electron component has been achieved in 10– 100 GeV and the energy spectrum has been obtained.

New principle of feeding for flash evaporation MOCVD devices

A novel scheme of flash evaporation feeding for MOCVD processes of multicomponent oxide films deposition is proposed. The scheme comprises 1) microdozage of organic solution of solid volatile precursors on the glass fiber belt, 2) evaporation of the solvent and 3) flash evaporation of MOC microdoses from the belt. The functioning of the designed feeder is described and the features of proposed scheme in comparison to existing feeding principles are discussed

Air-Jet Texturing of Spun Cotton Yarns for Improved Comfort

We have studied air-jet texturing of spun yarns with different structural configurations. After texturing, the yarns have improved bulk and reduced modulus and flexural rigidity, rendering them more suitable for improved comfort applications. Increased bulk after texturing is accompanied by reduced strength. We have observed that after air-jet texturing, certain structures such as carded ring spun yarns and Siro spun yarns possess a higher level of bulk compared to other structures. Rotor spun yarns have lower bulk after texturing because of their tripartite structure, twist angle variations, and the alternating Z and S helices in their fiber belts. Yarns with reinforced structures like composite spun, wrap spun, and rotor spun are able to withstand higher overfeed and air pressure during texturing.

Influence of Belts on Tensile Properties of Rotor-Spun Yarns

A small percentage of long fiber belts in a short-staple rotor-spun yarn improves the strength of the yarn, due to the reinforcement of yarn matrix through belts. It is observed that these long belts extend during tensile straining of the yarn and thereby increase the lateral compression on the yarn matrix. Cyclic stressing at 60% of average breaking extension shows that the presence of long fiber belts restricts fiber slippage during axial straining and reduces the extent of permanent deformation. The removal of belts of long fibers tends to produce similar tenacities in the cotton core.