The main disadvantages spatial structures are: increased requirements for the manufacturing elements accuracy; high consumption of material due to the having of "extra" elements; high material ...consumption due to the specified unification of elements. It is possible to reduce material consumption by searching optimal shape of the spatial structures and to refuse the idea of maximum unification of elements. A reduction in material consumption, if other things being equal, should provide a cheaper construction. The reasonable choice of the best project from the set of acceptable options can be made only with the use of optimization methods. The following are the author's suggestions on parametric optimization task formulation for spatial bar metal structures. To solve this problem, it is suggested to use a method of calculation similar to the method suggested by prof. Ya.I. Olkov. Proposed for use direct search method on all spatial construction nodes coordinates variation. In suggested method node coordinate change cause change in geometrical shpe of the whole construction. Geometrical shape changes cause original construction to turn to a new one. For all new constructions only original topology is similar. This method allows to analize effectiveness of constructions with the same topology but different: height; node amount; belt grids of various geometric shapes. It is proposed to organize the solution of the problem in the form of a dynamic iterative process in which several levels of cycles of enumeration of parameters are realized. To implement the solution of the described problem, we proposed a computer implementation algorithm.
For structural structures, there is a problem of high labor intensity of manufacturing nodal connections. In the nodes of structural structures can be paired about eighteen rods. The joints of ...structures are usually divided into two types. The known structures with the nodes of the leaves, with knots of massive details, with the nodes on the bolts with knots on the welding and stuff. Structures perceive external loads with all their elements, so each node connection is in a complex stress state. The design of the nodal connection determines the reliability and efficiency of the structural design. The reliability of the node spatial structures can be analyzed at design time by using advanced computational systems. that are executed based on the massive details (Mero, etc.) and nodes that are executed on the basis of thin metal sheets (Unistrat etc.). Techniques for optimal design of massive nodes and for nodes of the subtle elements are very different. The search for the optimal solution of the structural design unit can be organized in the form of an iterative process. Typically, nodes that are made from a massive part are very rigid. Internal stresses are distributed in the shortest directions from the load application areas to the support. Therefore, you can find little loaded areas in massive nodes. The material in these areas can be removed. Get a more efficient design of the node. Nodes made of thin sheet elements have a large deformability. The rigidity of the node has to be provided using special techniques. The internal stresses are locally concentrated. Therefore, it is necessary to look for solutions for local tightening and hardening of the node, for example, by installing ribs or local thickening of sheet metal parts. Improvement of the design of the unit can be achieved by adding material to its weaknesses. It is established that the results of calculations performed using different calculation complexes have acceptable accuracy of calculations. The error between the stress calculations performed in different calculation complexes does not exceed 10%.
Latticed metal spatial cover designs have many advantages over traditional structures, for example, in front of flat farms. However, their mass application is hampered by the following factors: the ...complexity of the implementation of nodal connections, the laboriousness of manufacturing, the laboriousness of transportation and installation. Another factor that restrains the widespread use of spatial factors is their little study. This is especially reflected in the restriction of the use of new structures or on the attempt of non-standard use of known structures, etc. The author of this work in his project practice used a structural plate as an inclined covering in a production building. The task in hand does not have a known direct analog of the already developed structural coating plate for use under the specified conditions. The authors proposed a new technical solution of the structural plate. The authors proposed to collect spatial structures by combining flat inclined trusses. All elements of flat trusses are proposed to be made from metal corners, and the nodes of trusses are made of sheet parts. To achieve this goal, the authors solved a number of problems: the refinement of nodal loads acting on the inclined spatial structure; the search for the optimal distribution of material within the spatial lattice structure; ensuring compliance of the designed structure with the current construction standards.
Modern "computer-aided design" (CAD) systems allow to process difficult researches on building structures of buildings and constructions. Program complexes, allowing to calculate and get performance ...predictions of materials and constructions made from them, considered as CAE (Computer Aided Engineering). CAE systems are used not only for creating and researching new materials, but also widely used for rating of traditional material condition. For brick chimney technical condition research program complexes SolidWorks and «Lira-W» were used. Using these calculation complexes structural rigidity, brickwork structures strength ratings were made, the need for taking measures to strengthen the construction was set. Using numerical researches, hazardous locations were identified along the height of the structure. For hazardous locations, a comparative analysis of obtained values of stresses in masonry was carried out in two calculation complexes.
Elements in the nodes of spatial bar structures can be assembled either with bolted connections or with welding. For welded nodal connections, each element should be attached separately. This ...complicates the process of manufacturing the structure and increases the labour input while assembling this structure. The so-called "tub welding node" does not have such flaws as several bars are joined by a single weld formed during a single pass of the welding machine. The weld of such a node is in a complex stress and strain state. It means that a relatively small weld should constantly take heavy loads. To assess the stress and strain state of the welding node, the researchers conducted numerical studies in the SolidWorks software system. The calculation model of the structural node was based on the results of a particular existing structure examination. These empirical numerical studies revealed that stresses are evenly distributed in the body of the weld, but its surface stresses exceed the stresses inside the weld. There are some areas on the weld surface that exceed the yield strength of steel. Still, the size of these areas is negligible.
Ainu is the only native minority language in Japan during the historical period. Its genetic relations are not known, its grammatical system differs from the systems of the languages of the ...surrounding peoples. The ethnical origin of Ainu is not well-known either. In the 19th century, native speakers of the Ainu language lived in Hokkaido, south Sakhalin, the Kuril Islands, and south Kamchatka. They were not numerous, but their linguistic situation was stable, and their contacts with other peoples were not significant. Their occupations were hunting and fishing. Since the 19th century, the Sakhalin Ainu and the Kuril Ainu began to move into Hokkaido. The Russian writer A. P. Chekhov visited Sakhalin in 1890 and described the Ainu situation. He wrote that the Ainu were peaceful and gentle people; they could not resist the Japanese expansion. At that time, the Ainu population of Sakhalin was declining; there were two causes thereof: death from starvation and migration to Hokkaido. However, since that time, Hokkaido was occupied by the Japanese people. Ainu lost their territory and did not have equal rights with the Japanese. The Japanese people despised Ainu, using the phonetic semblance of the name of the people (Ainu) and the Japanese word inu, ‘dog’, and considered Ainu a hybrid of people and dogs. The Ainu language had no writing system and only Japanese was taught in the Ainu schools. The Ainu people were in the process of assimilation. After the Second World War, the Japanese and the Ainu were equalized in their rights, but the new reforms did not change the linguistic situation, and the Ainu language became extinct very quickly. The last speaker of Ainu in Sakhalin died in 1975, and the last speaker of Ainu in Hokkaido died about 2000.
The article studies the effectiveness of different materials usage in building structures. Specific researches and estimates have been done to complete this study. Economic usage indicators of ...materials with different properties for creation of identical building structures were compared. Impact of the following material properties such as strength, elastic modulus, weight and cost on the construction cost was estimated. Rafter construction was selected as a study object. Calculations examples of rafter constructions made of wood and steel are described in the paper. Material properties impact on operational characteristics of the building structures was estimated. Variant design and optimal design of constructions made of materials that properties considerably differ were reviewed. Variant design example used in the building practice was described.
Abstract
Took into account experience of light metal constructions using in building. Paid attention to possible metal beams weight reducement ways. Interest to metal beams weight reducement appears, ...because they are widely used in modern building. Beams weight reducement is considered as an effective way of building spending reducement. The ways of reducing the material consumption of I-beams are formulated as manufacturing corrugated and perforated walls. Stress-strain state of corrugated beams numerical research results are shown. The results of solving the optimization task of finding the circular perforation geometry in the I-beam wall are presented. I-beam stress-strain state during bending under constrained torsion conditions research are presented. Made a conclusion about the efficiency of corrugated and perforated beams in comparison with traditional rolled beams. Concluded that it is necessary to take into account the stresses caused by the I-beam constrained torsion when the load adding eccentricity exceeds 15% of the flange width.
Many elements of spatial trussed structures are converged at the nodes. The structural assembly operates in a difficult stress state. It is possible to study the distribution of stresses inside the ...nodal connector, which is a massive part, using the calculated software systems. The authors performed a study of the MARKHI system node's stress-strain state, analyzed the surface stresses level and stresses inside the nodal connector.
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