Ag-ZnO co-sputtered films at various atomic ratios of Ag (Ag/(Ag + Zn) at.%) were prepared by a radio frequency magnetron cosputtering system, using the co-sputtered targets of Ag and ZnO. The activation of the Ag acceptors (AgZn) and the formation of the Ag aggregations (Ag0) in the ZnO matrix were investigated from XRD, Raman scattering, and XPS measurements. The Ag-ZnO co-sputtered film behaving like a p-type conduction was achievable after annealing at 350 °C under air ambient for 1 h.
Purpose
This paper aims to study the tensile performance, deformation characteristics, auxeticity and stability of different auxetic tubular structures generated by cutting method and pattern scale factor (PSF) method using validated finite element analysis.
Design/methodology/approach
Two types of auxetic tubular structures were designed by a coordinate transformation method and the PSF adjustment method, respectively. ABAQUS/explicit solver was used for the large deformation analysis and the displacement of key nodes was extracted to calculate Poisson’s ratio value and evaluate the deformation of tubular structures.
Findings
The random cut method was not suitable for designing auxetic tubular structures. Vertical and horizontal cut approach was suitable, but the change of the tubular diameter was lower than the tubular structures generated by the PSF adjustment method.
Research limitations/implications
Simple ways to generate auxetic tubular structure, which can be made into intelligent and foldable equipment, such as annuloplasty rings, angioplasty stents and oesophageal stents. By combined with shape memory polymer, various smart tubular materials and structures with various functions can be designed, especially in medical scaffold and other medical equipment fields.
Originality/value
The auxetic characteristic of tubular structure designed by using random cut method has been investigated for the first time. The outcome of this study would be very useful design tubular structures with better mechanical properties.
Under the high temperature of fire, the temperature change of the reinforced concrete beam is very important to the structure study. This paper, with heat transfer theory as its theoretical basis, explores the analytical method, the common method for analysis, calculation method of numerical value and finite element analysis by analyzing the temperature field of the concrete component cross sections under high temperature. With the help of MATLAB, it calculates and analyzes the temperature field of the reinforced concrete beam under the high temperature of fire, determines the temperature rise curve of the reinforced concrete beam in case of fire, and calculates the cross section temperature fields of the beam or pillar under the circumstances of different cross section sizes and different timings of fire on three sides.
The mechanical property of the concrete under high temperature will go through great changes with much greater deformation. The uneven temperature distribution causes equilibrium temperature stress of the cross section and deformation of components, thus damaging the structure system of the concrete. This paper conducts a high-temperature test on the C25 concrete specimen with fire retardant coating, compares the test result with the test on the C25 concrete specimen without fire retardant coating, and analyzes the protective role of the surface fire retardant coating in the concrete structure buildings in case of fire.
The determination of damping constitutes an essential part of the cyclic characterization of soils. While because of the damping of soils is nonlinear, ie., strain-dependent, the definition of shear strain amplitude under irregular loading process construct the key point of the damping based cyclic models. This paper introduces a new damping-based model (DBM) for nonlinear soil behavior simulation and discusses on the effect of shear strain amplitude definition on model behavior. Both qualitative and quantitative analysis re-sults show that the reversed hysteresis loading curve is significantly influenced by the pre-supposed loading amplitude and generally large pre-proposed shear strain amplitude will lead to low reversed loading trajectory. Analytical comparison among several definitions indicates that defining the maximum reversal point of history as the loading amplitude performs the best.
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