scholarly journals Methods of calculation of cold-formed structures

2021 ◽  
Vol 1209 (1) ◽  
pp. 012047
Author(s):  
E Hodovanets ◽  
M Al Ali ◽  
V Kvocak

Abstract Cold-formed structures are a separate type of metal structures and require more complex mathematical models in comparison with massive profiles. The development of main theories was described. A new type of buckling is also taken into account - warping, which is characteristic only of cold-formed bars.

Author(s):  
J. J. LUCHKO ◽  
V. V. KOVALCHUK

Purpose. The purpose of the work is to establish the real technical condition of transport structures made of corrugated metal structures on the basis of the analysis of scientific and technical sources.And to analyze the experience of operation of metal corrugated structures in the soil environment and to form and generalize the problems of ensuring the reliability and durability of structures made of metal corrugated structures in the conditions of operation on railways and highways of Ukraine. Methodology. To achieve this goal, a review of scientific and technical sources and regulations of different countries on the technical condition of transport facilities in Ukraine was conducted. In particular, data on the distribution of bridges and pipes made of corrugated metal structures by mode of transport are given. It is shown that the development and implementation of new technologies for the repair of existing defective pipes and small bridges, both on the railways and highways of Ukraine is a very important issue. A thorough analysis of the experience of operation of corrugated metal structures in the soil environment in different countries was conducted. Data on the main inadmissible defects of pipes and the reasons of their development are given. CMS' (corrugated metal structures) corrosion and other defects are given. A number of examples of overpass defects, collapse of bridges and structures with MCS in operation are presented. The qualitative indicators of metal corrugated structures, their advantages and disadvantages are also considered, the problems and the analysis of ensuring the reliability and durability of the structures with CMS in the conditions of operation on the railways and highways of Ukraine are formulated. Findings. An analysis of domestic and foreign scientific and technical sources on the technical condition of transport facilities in Ukraine was conducted. In particular, the experience of operation of corrugated metal structures in different countries of the world is studied and generalized. The analysis and synthesis of problems of ensuring the reliability and durability of buildings with CMS in the conditions of operation on the railways and highways of Ukraine. Originality. As a result of the analysis of the technical condition of transport facilities operated on railways and highways of Ukraine, it was found that about 15 % of transport facilities – small and medium bridges and culverts on Ukrainian railways and about 45 % of transport facilities on Ukrainian roads have unacceptable defects and require immediate repair and replacement. Also, it was established on the basis of research that there are no methods for assessing the load-bearing capacity of transport facilities with CMS in the presence in the body of the embankment of the railway or highway metal corrugated structures with a diameter greater than 6 m. It was determined that standards don't include regulations on design and monitoring of CMS on railway tracks. Practical value. On the basis of these data it was possible to offer directions of theoretical and experimental research and methods of calculation, tests of CMS and diagnostics of a technical condition of transport structures with CMS. In particular, the measurement of the impact of the environment on the bearing capacity of the CMS and the measurement of residual deformations of the corrugated metal pipe on the railway track. Execution of the analysis and synthesis of methods of calculation of transport constructions with CMS will lead to improvement of methods of calculation of CMS.


Aviation ◽  
2005 ◽  
Vol 9 (3) ◽  
pp. 9-18
Author(s):  
Arif Pashayev ◽  
Djakhangir Askerov ◽  
Ramiz Ali Cabar oqlu Sadiqov

In contrast to methods that do not take into account multiconnectivity in a broad sense of this term, we develop mathematical models and highly effective combination (BIEM and FDM) numerical methods of calculation of stationary and quasi‐stationary temperature field of a profile part of a blade with convective cooling (from the point of view of realization on PC). The theoretical substantiation of these methods is proved by appropriate theorems. For it, converging quadrature processes have been developed and the estimations of errors in the terms of A. Ziqmound continuity modules have been received.


2014 ◽  
Vol 989-994 ◽  
pp. 1127-1130
Author(s):  
Ying Xu

Ecological city, in a broad sense, is a new cultural notion based on mankind’s profound understanding of the relationship between human and nature, new-type social relationship in accord with ecological rules which coordinate society, economy and nature, and also a sustainable lifestyle. In a narrow sense, ecological city is a highly effective, harmonious and healthy environment where people gather.


2018 ◽  
Vol 224 ◽  
pp. 05009 ◽  
Author(s):  
Aleksey Dorokhov ◽  
Victor Khamyev ◽  
Kirill Lepeshkin

As a result of the analysis of developed earlier mathematical models of the process of seeds purification on a two-tier lattice mill of polymeric materials the possibility of significant improvement in the quality of seed treatment and performance at the same quality at the expense of more rational technological schemes and modernization of the sieve camp’s were revealed. Constructive changes were made in the lattice mill with using a new type of polymer sieves. Result of this experimental studies confirm the identified possibility of intensification of the process of seed cleaning - completeness of waste allocation increased from 0,653 to 0.75, i.e. 15 %, performance for the same quality of cleaning have increased by 24%.


2012 ◽  
Vol 479-481 ◽  
pp. 1421-1428 ◽  
Author(s):  
Jian Wang ◽  
Liang Hou ◽  
Shan Ming Luo

A new type of spherical gear drive, which takes micro-segment involute profile as tooth profile, is presented in this paper. The generation principle of the spherical gear is described. The mathematical models including the equation of micro-segment involute profile, the equation of the conjugate tooth profile and the engagement equation, are established based on the meshing theory. This new type of spherical gear drive has the potential to improve the load capacity and the performance of spherical gear transmission.


1993 ◽  
Vol 8 (5) ◽  
pp. 1010-1018 ◽  
Author(s):  
Carey A. Pico ◽  
Tom D. Bonifield

The formation of hillocks has been studied as a function of process parameter in patterned and unpatterned Al98.5wt. %Si1.0wt. %Cu0.5wt. % films deposited on chemical-vapor-deposited W-coated substrates. The effects of linewidth, substrate temperature during film deposition, and sintering time and temperature on hillock size were investigated. Three types of hillocks are found: the “surface hillocks”, the “side hillock”, and the “line hillock”. These are further classified by their shapes. The surface hillock and side hillock, which have been seen previously, form on patterned metal lines having linewidths greater than the larger Al alloy grain sizes (~3 μm). None is seen on linewidths between 0.9 and 2 μm where long-range grain boundary diffusion cannot occur. A new type of hillock, the line hillock, is seen to occur on metal structures having linewidths of 0.6 μm. The line hillock is inconsistent with the current understanding of hillock formation and may present severe restrictions on the downsizing of ultra-large-scale integrated devices.


2014 ◽  
Vol 496-500 ◽  
pp. 1473-1476
Author(s):  
Qi Zhang ◽  
Ying Jun Li ◽  
Gui Cong Wang ◽  
Ru Jian Ma ◽  
Xiu Yun Zhao

A new type of upper and lower cover support structure piezoelectric sensor based on PVDF films is designed in terms of piezoelectric effect. Mechanics and mathematical models are established according to the structure of the sensor. The natural frequency of the sensor is derived finally. The natural frequency of the sensor is verified to meet the requirements of dynamic measurements by using theoretical calculations and simulations. The effectiveness of the calculating method is indicated.


1996 ◽  
Vol 15 (3) ◽  
pp. 107-113 ◽  
Author(s):  
Vladimir A. Magdenkov

Samples of new self-adhesive, constrained vibration-damping coatings (VDC) and layers for “sandwich” type plates for damping flexural waves in plates are described. These coatings consist of aluminium foil, perforated cardboard and layers of self-adhesive viscoelastic material. The results of measurements of the temperature-frequency characteristics of the loss factor of flexural waves in plates which are damped with these coatings are given. Methods of calculation of viscoelastic characteristics of multi-layer constructions are considered. The peculiarities of use of constrained and hard vibration damping coatings are investigated on the first natural frequencies while damping flexural waves of plates and beams, clamped at their edges.


2010 ◽  
Vol 42 ◽  
pp. 303-306
Author(s):  
Bao Zhan Lü ◽  
Ai Jun Hu ◽  
Si Hong Zhu

Based on the analysis of vibration characteristics of certain off –road vehicle, and research of effect of front axle suspension to vehicle and parameter matching, a new type of damping-adjustable hydro-pneumatic suspension was put forward. After the analysis of its working principle, the nonlinear dynamic mathematical models of this suspension were set up. Using the method of theoretical calculation and simulation by MATLAB/Simulink, the characteristics of damping force of this damping-adjustable hydro-pneumatic suspension were studied.


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