Forecasting the life of a structure relative to the operating mode

The question of forecasting the service life of transport machines designed by taking into consideration the load spectrum, that is close to the real one, is an important problem at the calculation. One of the ways to simulate real operating conditions at the design calculation is a method of randomization quasirandom loads. Methods of randomization are widely used in many areas of science and technique. In the article, the numeric comparison of different ways of randomization is shown at the calculation for determining the service time using two techniques: the use of a standardized function of randomization in the high-level programming language of the and the law of normal distribution at its different parameters. The use of the law of normal distribution makes the more exact fatigue calculation because it makes it possible to simulate the quasirandom process that corresponds to the real operation picture to a greater degree. The results presented in the work make it possible to fulfill the calculation of the service time of the metallic structure that is under cyclic asymmetric loads, at the well-known nature of the application of loading to it.

Experimental Realization of Sub-THz Circularly Polarized Antenna Based on Metasurface Superstrate at 300 GHz

This communication presents a low-profile fully metallic high gain circularly polarized resonant cavity antenna, with a novel single-layer metasurface as superstrate operating at 300 GHz. The unit cell of the metallic metasurface layer consists of perforated grids of hexagonal and octagonal-shaped radiating apertures. The metasurface superstrate layer acts as a polarization convertor from linear-to-circular, which provides left-handed circularly polarized (LHCP) radiation. For simplicity and less design difficulty, a low cost laser cutting brass technology is proposed to design the antenna at sub-terahertz. The proposed circularly polarized resonant cavity antenna prototype has a low-profile planar metallic structure of volume 2.6λ0×2.6λ0×1.24λ0. Experimental results validate the design concept. The antenna yields a measured LHCP gain of 16.2 dBic with a directivity of 16.7 dBic at 302 GHz. This proposed circularly polarized resonant cavity antenna finds potential application in 6G sub-terahertz wireless communications.

Tuning and Sensitivity Improvement of Bi-metallic Structure-based Surface Plasmon Resonance Biosensor with 2-D ξ-Tin Selenide nanosheets

This manuscript aims to visualize the effect of tin selenide (SnSe) on the sensing application of the SPR biosensors. Tin selenide is the 2-Dimensional material transition metal dichalcogenide family element. By utilizing the extraordinary properties of the SnSe, high sensitivity and high performance of the biosensor is analyzed by utilizing the extraordinary properties of the SnSe. A unique two-dimensional substantial heterostructure, \({\epsilon }\)-tin selenide (SnSe) /graphene layer has been deposited over the metal surface to improve the sensitivity; moreover, the sensitivity is limited to a certain extent. The \({\epsilon }-\text{S}\text{n}\text{S}\text{e}\) nanosheet is placed in between two layers of gold (Au) in the Kretschmann arrangement. The proposed configuration has a maximum sensitivity of 214°/RIU, which is 93.81% higher than the conventional sensor. The performance parameters like FWHM, detection accuracy and quality factor have been analysed. The \({\epsilon }-\text{S}\text{n}\text{S}\text{e}\) material is an air-stable 2-D nanosheet and has application in chemical, medical, and biological sensors.

Design and Optimization of a Curved-Crease-Folding Process Applied to a Light Metallic Structure

Presently, the realization of complex, unconventional designs using efficient modalities is possible due to an increasing interest in interdisciplinary approaches: materials science, mathematics, IT, architecture, etc. Computerized techniques, among which the algorithmic/generative design is the most advanced one, that are associated with the individualized production methods are used for finding solutions for modern spatial forms with an unconventional spatial geometric shape, which are generically called “free-forms”. This work presents the design, realization and testing of a thin-walled metallic structure proposed as a light structural unit. An integrated research approach was proposed that utilized an algorithmic/digital design applied to the curved-crease-folding method with the study (at different length scales) of the metallic material behaviour after folding. An original method was proposed for the digital design and simulations. The specific mechanical behaviour of the metallic material in the elastic–plastic regime was used in this case to improve the structural performances; mechanical and structural tests were realized to analyse the behaviour of the entire structure. The results are useful for enhancing the accuracy of the digital design, the structural simulation programs and the fabrication methods.

Design of Wideband Bandpass Filter Based on Corrugated Disk Resonator with Multiple Resonant Modes

A corrugated disk resonator with eight grooves is proposed for wideband bandpass filter (BPF) design. Due to the spoof localized surface plasmons resonances of the corrugated metallic structure, the dipole, quadrupole, hexapole modes, and a fundamental mode excited by the introduced short-circuited via holes are employed to realize four transmission poles (TPs) in the passband. The theoretical analysis is described by the electric field and current distributions on the resonator. The resonant frequencies can be tuned easily by the parameters of the structure, which can be used to adjust the center frequency and bandwidth of the BPF freely. Furthermore, two resonators are cascaded to obtain eight TPs to improve the selectivity performance. Finally, three fabricated filters demonstrate the design method.

Parametric Analysis of the Dome of the Sports Palace of Mexico City

The Sports Palace of Mexico City was built in 1968 and became a turning point in the design and construction of laminar shells, leading the transition from reinforced concrete to metallic grid structures. Felix Candela observed that the use of concrete in designing laminar structures was limited to achieve great spans for sport spaces; he thus changed his first proposal for using a concrete laminar shell to a metallic structure. However, in the first architectural conception of the metallic structure, a lighter cable structure was proposed respecting the built geometry, with the intent of using high-strength wires in the upper and lower chords of the arches. In this paper, three different proposals are modeled. The first uses a 3D modelled concrete shell for understanding the geometry. The others use the final geometry and are analyzed using advanced NURBS (Non-uniform rational Bspline) modeling techniques with Rhinoceros and a parametric design with Grasshopper, where the parameters and results obtained in previous tests are compared with the results obtained in the simulations. Paneling plugins, forces simulation add-ons, finite elements analysis and environmental design simulation tools in Grasshopper are used to compare the results under normal design conditions.