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Inorganic materials face enormous challenges in designing and processing flexible devices that can be stretchable, crimped and folded. Organic materials have attracted wide attention because of their flexible properties and advantages in manufacturing flexible electronic devices. In this study, the flexible organic microcircuit pattern of poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) material was fabricated by using the near-field electrohydrodynamic direct -writing method, the experimental results show that the bending deformation of the flexible substrate with different curvatures has no effect on the conductivity of the microcircuit pattern deposited on the flexible substrate, which has no effect on the performance of the flexible microcircuit pattern. In order to improve the conductivity of the flexible organic electronic microcircuit, the multi-layer microcircuit pattern was fabricated by using the near-field electrohydrodynamic direct-writing method. With the increase of the number of the direct-writing micro-pattern layer, the conductivity of the microcircuit patterns sintered at 105 °C for 10 min increase from 168.32 to 313.05 S/cm. Atomic force microscope was used to observe the morphology of the direct-writing microcircuit patterns. With the increase of the layer number of the microcircuit pattern, the internal density of the microcircuit pattern increases, and the microcircuit-pattern morphology becomes smoother. The experimental results show that the multi-layer direct- writing method can effectively improve the conductivity of the flexible organic electronic microcircuit pattern. This study provides a new method to fabricate the flexible organic microcircuit pattern with high conductivity by a non-contact and low-cost mode. [ABSTRACT FROM AUTHOR]

Large seabed trenches have recently been found adjacent to suction caissons with taut and semi-taut moorings. Seabed trenching leads to loss of soil support and additional caisson rotation, and can therefore significantly decrease geotechnical capacity. In this paper, upper-bound solutions are presented that enable calculation of the reduction in ultimate load-carrying capacity of a suction caisson in a trenched seabed compared to optimal capacity in an intact seabed. Failure mechanisms for caissons embedded in an intact seabed are augmented to incorporate a kinematically admissible mechanism for a trench extending from the mudline. The rate of work dissipation is calculated to determine the optimised solution of the inclined capacity of suction caissons. Comparisons of the results of the upper-bound solutions with finite-element analyses show that the failure mechanisms and the calculated load-carrying capacities derived from the two methods agree well. Therefore, the analytical upper-bound method presented in this paper can be employed for efficient routine calculations of suction caisson capacity under inclined load considering seabed trenches, which are increasingly encountered in engineering practice. [ABSTRACT FROM AUTHOR]

The influence of a polypropylene fiber on the tensile properties of a cement-polymer based thin spray-on liner (TSL) was investigated in this study. Two different contents of fiber were added to the liner, yielding two TSL groups. Tensile tests were performed (in accordance with the ASTM D638 standard) on the two groups of specimens as well as the control group at 1, 7, 14, and 28-day curing. The test result verified the large plasticity and low elastic modulus of the TSL compared with the fiber. SEM examination revealed that fibers lying parallel to the load direction ruptured or were pulled out from the matrix, which was beneficial to the tensile strength, but detrimental to the elongation because of their high stiffness. Other fibers lying perpendicular with the load direction were detrimental to both tensile strength and elongation through aggravating the propagation of the cracks. The tensile strength was improved by fiber incorporation, while the elongation was reduced at all curing. The influence of fibers on tensile toughness was uncertain since tensile toughness depended on strength as well as deformity. [ABSTRACT FROM AUTHOR]

Highlights • Short encapsulated cyclic thrust tests conducted on prepared bolting system. • Mechanical response and acoustic emission properties analysed and compared. • Strengthening effects, creep behaviour, Kaiser effect, bearing capacity, etc. evaluated. • Reasonability, scientificity, and deviation of the testing method discussed. Abstract Research on bolt reactions under cyclic disturbance is still sparse due to complex and special laboratory processes. This paper endeavours to reveal the mechanical response and acoustic emission (AE) characteristics of bolts under cyclic loading, and a series of short encapsulated cyclic thrust tests (SECTTs) was conducted. First, the threshold determining stress level in the cyclic process was defined based on monotonic thrust tests, and the stress distribution along the steel tube was obtained simultaneously. Second, tests specified by staged cyclic loading with varied cyclic counts at each stage were conducted, and the influence of the cyclic count on the stability of the bolting system was evaluated. Third, tests specified by staged cyclic loading with holding intervals were conducted, and the creep behaviour of the bolting system was investigated. Controlling factors such as frequency, amplitude, and cyclic count were comprehensively considered. Fourth, two tests specified by staged cyclic loading with high cyclic count were conducted, and the influences of high cyclic count were discussed. Generally, a short encapsulated bolt undergoing cyclic loading behaved differently from a statically loaded bolt, and some interesting results were observed based on analysis of AE properties, strengthening effects, creep behaviour, failure prediction, bearing capacity evaluation, etc. At the end of this study, the reasonability and deviation of SECTT adopting steel tubes to simulate rock masses in the laboratory were discussed. [ABSTRACT FROM AUTHOR]

Abstract Floating structures are often secured in position with a taut mooring system and suction caissons. Large seabed trenches have been observed adjacent to some suction caisson anchors with taut-line mooring systems. The trenches may jeopardise the geotechnical capacity of the caissons and in turn the stationkeeping of the floating structures. Finite-element method is employed to examine the geotechnical capacity of suction caissons in a trenching seabed. The results show that the reduction in the geotechnical capacity becomes more significant with increasing trench width due to the loss of soil support and a change in failure mechanism as the caisson rotates into the trench. For a given trench width, the reduction in capacity becomes more significant as the load inclination angle to the horizontal decreases. However, the shape of the normalised failure envelopes for combined vertical and horizontal load is insensitive to trench width. A strategy to design for inevitable trenching by moving the padeye shallower to reduce the depth of trench formation is not straightforward. The gain from a shallower trench may often be outweighed by the reduction in capacity from rotation of the caisson at failure for loading angles typical of taut moorings. Highlights • Geotechnical capacity of the suction caisson anchors exposed to large seabed trenches. • Governing soil flow failure mechanisms around suction caisson anchors in trenching seabed. • The effects of trench configurations, caisson-soil interface conditions and loading paths are examined. • Design for inevitable trenching by moving the padeye to a shallower depth is not straightforward. • A strategy to overcome the challenge of seabed trenching is presented based on a case study. [ABSTRACT FROM AUTHOR]