The effects of preloading on tensile properties of braided polyarylate fiber ropes

In the present work, the effects of preloading on the tensile properties of braided polyarylate fiber ropes were investigated experimentally. Four kinds of samples with different pitch lengths were tested with designed preload levels. The deformation responses of the ropes were captured using digital image correlation (DIC) and micro-computed tomography (micro-CT). It is shown that the nonlinearity in the mechanical behavior of the ropes can be almost eliminated post-preloading with one cyclic loading, and the transverse strains are much greater than the longitudinal strains due to the compaction of rope structure because of the spiral interlaced path of braid yarns. The rope with shorter pitch length (larger braid angle) has larger longitudinal strain and smaller transverse strain due to the higher yarn crimp rate and tighter yarns, respectively. The preload level is the most important parameter for preloading. The chord modulus of the ropes reached an optimum level at the preload level of 40% break load, and the tensile strength can be increased by 15% at the preload level of 50% break load. Moreover, the stability of the tensile properties could be accelerated at the higher preload level. Consequently, preloading is vital to improve the tensile properties of braided polyarylate fiber ropes, with a preload level at least of 40% break load and 10 cyclic loadings.

Structural design and characterization of highly elastic woven fabric containing helical auxetic yarns

Auxetic textiles have been the focus of much attention due to their great promise for advanced protective clothing, flexible energy harvest devices, and functional textiles. Herein, plain fabric, basket fabric, and a derivative weave with the warp and weft yarns arrangement in a series of zigzags were prepared by incorporating different initial wrap density helical auxetic yarns in the weft direction using a commercial semi-automatic loom. The derivative weave using HAYs with a 150 m−1 initial wrap density as the weft yarn not only possesses superior auxetic behavior but also has good performance in strength and elasticity—essential properties useful for textile daily application. This fabric exhibits a high auxetic effect ( ν = −0.585), low elastic deformation (total deformation of 8.4% at 20% strain), excellent flexibility, and high break load. Moreover, by taking account of the key geometric parameters, a systematic discussion of the fabrics has been completed to evaluate the effect on the auxetic behavior; this clarified that changing the fabric structure and initial wrap density of a HAY is an effective strategy to tailor auxetic behavior without compromising the intrinsic properties of components. On the basis of our research, auxetic textiles can be considered a promising candidate for next-generation smart textiles and advanced functional textiles.

Inner Bend Cracks in Mooring Chain: Investigation of Cracks Observed on Chains Taken Out of Service

The last decade Equinor has taken a significant amount of mooring chains out of service. Typically, one mooring line for an offshore installation has been replaced. Purpose has been to assess whether current chain condition (corrosion and wear), make the remaining chains fit for further use. The chains have been subject to thorough inspection, break load testing and fatigue testing. Depending on results of the inspection and tests, the remaining mooring chains have either been replaced or found fit for further use. From one installation, smaller cracks on the inside of the crown of chain links have been observed. These cracks do not coincide with known fatigue hot spots or fatigue breakages from fatigue testing of chains. Many cracks are visible with the bare eye, and NDT techniques are not necessary for detection. Chains with such cracks have been subject to both break load testing and fatigue testing. Overload breakage and fatigue cracks have not occurred or developed from the cracks. Chain links with cracks have been dissected to investigate crack depth. Dissection has also aimed to assess the age of the cracks. Both chain links that have and have not been subject to full scale fatigue testing have been dissected. This paper presents example of the observed cracks, including details on link location in the mooring line, crack positions in links, and measured depth and length of cracks. The paper also discusses the different possible causes of the cracks, and whether the cracks are critical for the endurance of the chains.

STANDART PELAYANAN MINIMAL (SPM) DAN SISTEM LASING PADA KAPAL RO-RO UNTUK KESELAMATAN TRANSPORTASI PENYEBRANGAN LAUT (Studi Kasus KMP. LEGUNDI)

Zulfaidah Ariany, A Hendra, Samual Febriary, in this paper explain that LEGUNDI is a Passanger Ship which has a Surabaya - Lombok shipping route capable of transporting passengers and vehicles in relatively large numbers. Research Minimum Service Standards (SPM) and Lasing System on Ro-Ro Ship for Marine Transportation Safety is aimed to know about Minimum Service Standards (SPM) and how to handle the Lasing system on Ro-Ro KMP LEGUNDY. The reference used is Minister of Transportation Regulation no 30 of 2016 regarding minimum service standard. The analysis used is simulation of shear load calculation on vehicle in Car Deck so get output layout of vehicle parking layout. The result of simulation of the calculation got the total load when the car shifted 35,5 KN then it can be suggested using breaking strength: 60 kN (6 ton) and Weight 0.35 kg based on Break Load Capacity Table for Chain Lasingbe typed in one paragraph and one-column format.

The Response Analysis of Angle Tower Line System by Broken Lines

The suddenly break makes the tension of tight lines rapid realease. The tower system will be subject to impact,but the design specification considers the break load only by static load.Beacuse of the angle between the sides of the transmission lines and the span changes, In order to solve this problem this paper uses the finite element program ANYSY/LS-DYNA to build tower and lines system model and analyse the dynamic response of corner tower system in role of lines breaking by the numerical simulation. The study has shown that the effect of the corner to the corer tower disconnected power respose can not be ignored.

Physical characteristics of catheters used for subarachnoid drainage

BackgroundCerebrospinal fluid diversion through lumbar drainage catheters is a routine procedure that is used in a variety of clinical applications. Fracture of catheters during insertion or removal may result in retained foreign bodies that may lead to patient morbidity with potential legal ramifications. Fracture resistance is an important component of drain selection.ObjectiveTo analyze catheter integrity to determine which commercially available catheters are most robust and resistant to fracture.MethodsPhysical properties of the commercially available drainage catheters that can be advanced through a Touhy needle were assessed using laboratory equipment and reported. Five types of catheter were analyzed for break load, tensile strength, extension at break, and shear strength.Results and conclusionsOf the five types of catheter, the Arrow catheter showed the greatest resistance to fracture. Of the drainage catheters, the Codman catheter showed the greatest resistance to fracture.

Investigation of Tensile Properties of Manila Fibre Reinforced Composite

In the present scenario, composites are beginning to play a major role in day to day applications. Suitable properties can be imparted by selection or orientation of fibers during the manufacturing process. This paper demonstrates the natural composites made up of Manila as reinforcing agent with epoxy resin as matrix enclosed between glass fibers. Glass fibers, also known as woven rovings, are used to improve the surface finish and provide better strength and rigidity to the composite. Using hand lay-up method, fibers of Manila are arranged in alternate layers. The strength of composites depends on the fiber-matrix interfacial bonding. Three composite samples are prepared and mechanical stability of the composite is determined by tensile test. It is seen that there is not much variation in the ultimate strength of the three samples. On an average, it is found that average break load of the composite is 4.8 KN and the corresponding displacement is 9.08 mm. All the three samples exhibit almost similar elongation of about 18 % and the average ultimate tensile strength is 31.66 MPa. The reason for uniform tensile properties is due to a homogeneous distribution of fibers in all the three samples.

Study on the Relationship between Structures and Properties of Kevlar String

The relationship between structures and properties of Kevlar string was studied scarcely before, although the string was used in aerospace, spaceflight, ocean and the like. Kevlar braiding strings were designed and braided with different braiding angle, different core yarn content and different twist, and stretching properties were measured and analysed in the paper. The result shows that the bigger braiding angle is and the more core yarn content is, the higher break load is and the lower break elongation is. Besides, rupture analysis proves that braiding Kevlar bundles take hold of core Kevlar bundles tightly, both form an inseparable integrity almost during stretching. As a result, a special phenomena occurs, core Kevlar bundles are broken into several segments.

Influence of Fibre Stiffness on Deepwater Mooring Line Response

Polyester fibre ropes are now an accepted solution for deepwater mooring of production platforms and a single high tenacity fibre grade is widely used. Few studies of other fibres have been reported but polyesters can be produced with a range of properties by varying drawing parameters, and other stiffer fibres are also available. This paper presents a study of these alternative fibre rope solutions, performed within the French Mooring Line project. First, in order to obtain the input data necessary for mooring line analyses an extensive test program was performed to characterize polyester, improved polyester, PEN, LCP, aramid and HMPE fibre ropes from yarns up to 800 ton break load ropes. Tests at different scales have allowed property transfer to be quantified. Rope modelling has been used in parallel to examine the influence of material and structural parameters. Then, using these data, a series of analyses was run by engineering contractors, which quantified the benefits of higher stiffness for different supports (semi-submersible, production platform and offloading buoy) down to 2500 meter depth. Under certain conditions the stiffer ropes can result in significantly reduced rope diameter and weight.