Experimental Study on the Influence of Cross-Section Type of Marine Cable Conductors on the Bending Performance

Through the development of marine energy,marine cables are the key equipment for transmission of electrical energy between surface platforms and underwater facilities.Fatigue failure is a critical failure mode of marine cables.The bending performance of the cable conductor has a major influence on both bending and fatigue performances of the overall cable structure.To study the influence of different types of the conductor cross-section on the bending performances of marine cable conductors,three types of copper conductors with the same cross-sectional area,i.e.,noncompressed round,compressed round,and shaped wire conductors,were selected.The experimental results demonstrated that the cross-section type significantly affects the bending performances of copper conductors.In particular,the bending stiffness of the shaped wire conductor is the highest among the three conductor types.Four key evaluation parameters,i.e.,the bending stiffness,maximum bending moment,envelope area,and engineering critical slip point,were selected to compare and analyze the bending hysteresis curves of the three copper conductors.The differences in the key evaluation parameters were analyzed based on the structural dimensional parameters,processing methods,and classical bending stiffness theoretical models of the three copper conductor types.The results provide an important theoretical guidance for the structural design and engineering applications of marine cable conductors.

Bending performance analysis on YBCO cable with high flexibility

In order to utilize high‐temperature superconducting Yttrium Barium Copper Oxide(YBCO)tapes to develop superconducting cables for high magnet field applications,it is critical to ensure the stable operation of the YBCO cable under challenging mechanical and thermal conditions.A new type of cable featuring the winding of YBCO and copper tapes around a spiral stainless steel tube has been proposed to increase flexibility and cooling.Experiments are performed to confirm that its critical current varies with the bending diameter.The cables wound with nine YBCO tapes in three layers show a critical current degradation of less than 5%for a bending diameter of 30 mm.The performance of the cable degrades as the number of wound layers increases.The critical current degradation of cable specimens wound from 15 tapes in five layers reached approximately 12%for a bending diameter of 30 mm.In addition,when compared to traditional CORC cable specimens,the developed cable specimens show better‐bending flexibility and achieve a lower critical bending diameter.The finite element models show that the higher elasticity coefficient and lower plasticity of the stainless steel spiral tube results in a lower strain on the YBCO tapes of the HFRC cable than that of the CORC cable,and the maximum strain on the YBCO tapes of the HFRC cable was only about 10%of that of the CORC cable.Therefore,it is less likely that the YBCO tape in this type of cable will reach the irreversible strain limit during bending,resulting in a degradation in current carrying performance.Furthermore,the cooling efficiency can be improved by flowing the cooling medium inside the central core,which can significantly improve its thermal stability.These advantages indicate the possibility of using it in future high‐field magnets with high current carrying capacity at fields greater than 15 T.

Performance enhancement of sandwich panels with honeycomb–corrugation hybrid core

The concept of combining metallic honeycomb with folded thin metallic sheets （corrugation） to construct a novel core type for lightweight sandwich structures is proposed. The honeycomb-corrugation hybrid core is manufactured by filling the interstices of aluminum corrugations with precision-cut trapezoidal aluminum honeycomb blocks, bonded together using epoxy glue. The performance of such hybrid-cored sandwich panels subjected to out-of-plane compression, transverse shear, and three-point bending is investigated, both experimentally and numerically. The strength and energy absorption of the sandwich are dramatically enhanced, compared to those of a sandwich with either empty corrugation or honeycomb core. The enhancement is induced by the beneficial interaction effects of honeycomb blocks and folded panels on improved buckling resistance as well as altered crushing modes at large plastic deformation. The present approach provides an effective method to further improve the mechanical properties of conventional honeycomb-cored sandwich constructions with low relative densities.

Experimental Evaluation of Flexural Behavior of Stress Laminated Timber Decks

Stress laminated timber(SLT)deck is assembled using timber(umber or glulam)components placed side by side and stressed together,which has the advantages of easy prefabrication and good cost performance.This work pre-sented an experimental investigation of bending tests per formed on SLT slabs.Several parameters,including pre-stress levels,distance of pre-stressing bars,and the existence of self tapping screw(STS)reinforcement,were taken into consideration.To reinforce the compressive property of timber perpendicular to the grain,the STSs were placed under the anchor plate of the pre-stressed bars.The experimental results were analyzed and discussed in terms of failure modes,ultimate bearing capacity,ultimate strain,and bending sifness.It was found that the SLT slab showed satisfactory composite action as well as resid ual bearing capacity.The pre stress levels showed an obvious effect on the load bearing capacity and relatively slight effect on the bending stiffness.

Effects of SiO_2 and TiO_2 on resistance stabilities of flexible indium-tin-oxide films prepared by ion assisted deposition

Inorganic buffer layers such as SiO2 or TiO2 and transparent conductive indium-tin-oxide （ITO） films were prepared on polyethylene terephthalate （PET） substrates by ion assisted deposition （IAD） at room temperature, and the effects of SiO2 and TiOzon the bending resistance performance of flexible ITO films were investigated. The results show that ITO films with SiO2 or TiO2 buffer layer have better resistance stabilities compared to ones without the buffer layer when the ITO films are inwards bent at a bending radius more than 1.2 cm and when the ITO films are outwards bent at a bending radius from 0.8 cm to 1.2 cm. 1TO films with SiO2 buffer layer have better resistance sta- bilities compared to ones with TiO2 buffer layer after the ITO fdms are bent several hundreds of cycles at the same bending radius, for the adhesion of SiO2 is stronger than that of TiO2. The compressive stress resulted from inward bending leads to the formation of more defects in the ITO films compared with the tensile stress arising from outward bending. SiO2 and TiO2 buffer layers can effectively improve the crystallinity of ITO films in （400）, （440） directions.

Performance of steel bridge deck pavement structure with ultra high performance concrete based on resin bonding

This research investigated a pavement system on steel bridge decks that use epoxy resin(EP)bonded ultra-high performance concrete(UHPC).Through FEM analysis and static and dynamic bending fatigue tests of the composite structure,the influences of the interface of the pavement layer,reinforcement,and different paving materials on the structural performance were compared and analyzed.The results show that the resin bonded UHPC pavement structure can reduce the weld strain in the steel plate by about 32%and the relative deflection between ribs by about 52%under standard axial load conditions compared to traditional pavements.The EP bonding layer can nearly double the drawing strength of the pavement interface from 1.3 MPa,and improve the bending resistance of the UHPC structure on steel bridge decks by about 50%;the bending resistance of reinforced UHPC structures is twice that of unreinforced UHPC structure,and the dynamic deflection of the UHPC pavement structure increases exponentially with increasing fatigue load.The fatigue life is about 1.2×10^(7) cycles under a fixed force of 9 kN and a dynamic deflection of 0.35 mm,which meets the requirements for fatigue performance of pavements on steel bridge decks under traffic conditions of large flow and heavy load.