Modern structures of metal and wood最新文献

{"title":"CALCULATION OF INTERMEDIATE SUPPORTING PARTS OF INSEPARABLE PERFORATED BEAMS IN THE SOFTWARE COMPLEX «LIRA»","authors":"V. Romaniuk, V. Supruniuk, L.I. Bezniuk","doi":"10.31650/2707-3068-2021-25-130-138","DOIUrl":"https://doi.org/10.31650/2707-3068-2021-25-130-138","url":null,"abstract":"Due to the simplicity of design and manufacture, as well as reliability during operation, beams are one of the most common elements used in industrial, civil and public construction. The most rational cross-section of metal beams are rolled I-beams with inclined or parallel inner faces of the shelves, the predominant use of which is due to the value of the core distance, which is twice as much the same value for a rectangular section and almost three times for a round section. This figure is even higher for perforated profiles obtained from conventional rolling beams, which allow you to compose sections with increased values of moments of inertia and moments of resistance without increasing material consumptions. For inseparable beams, an additional significant factor influencing on their bearing capacity, is the structural design of the intermediate support part. The aim of these researches is to study the stress-strain state of inseparable perforated beams of I-beam profile of different heights in areas near the intermediate support, the design of which is made without a transverse stiffening rib placed on the axis of the support, and with unwelded holes to the left and right of the support under the action of evenly distributed load in the software complex \"Lira\". The objectives of the study are to establish the actual values of stresses and strains in the characteristic cross sections of the inseparable perforated I-beam, which occur on the intermediate support, and perform a comparative analysis of numerical studies obtained in the software complex \"Lira\" for intermediate support node beams of different heights for actions of different magnitudes of loads. The analysis of the obtained diagrams of normal stresses was carried out, which showed that for the proposed design of the support part of the beam, the cross-sections with holes directly to the left and right of the support are calculated. The conclusion about necessity of carrying out further experimental-theoretical researches of various types of support parts of beams for the purpose of development of a complex technique of their calculation and recommendations on definition of rational scope of application of each of them is formulated.","PeriodicalId":365885,"journal":{"name":"Modern structures of metal and wood","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129905439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"OPTIMIZATION OF CALCULATION SCHEMES","authors":"I. Medved","doi":"10.31650/2707-3068-2021-25-85-91","DOIUrl":"https://doi.org/10.31650/2707-3068-2021-25-85-91","url":null,"abstract":"Any calculation is preceded by the stage of creating a design diagram of a real structure, which would most accurately correspond to real operating conditions. The more optimally the design scheme is drawn up, the less laborious the stages of calculation and design of the corresponding structure will be. There are practically no results of using this approach when calculating building structures. This article attempts to show the possibility and expediency of using the \"Search for solutions\" (add-on for Microsoft Excel) at the stage of choosing the optimal parameters of the design design schemeAny calculation is preceded by the stage of creating a design diagram of a real structure, which would most closely correspond to real operating conditions. The more optimally the design scheme is drawn up, the less laborious the stages of calculation and design of the corresponding structure will be. If the efficiency criterion is a linear function, and the variables in the constraint system are also linear, then such a problem is a linear programming problem. Of the listed methods of mathematical programming, the most common and developed is linear programming. To illustrate the idea of the proposed approach, a simple statically definable truss on two supports was deliberately chosen. This is done so that the idea of the proposed approach is not lost due to the complexity and cumbersomeness of the calculations. This article shows the possibility and feasibility of using the \"Search for solutions\" at the stage of choosing the optimal parameters of the design design scheme. After the design scheme has been defined, more powerful conventional means of calculating building structures can be involved for its complete calculation.","PeriodicalId":365885,"journal":{"name":"Modern structures of metal and wood","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128562735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"KNEE JOINT OF THREE-HINGED GLUED TIMBER PORTAL FRAME EXECUTED AS JOINT ON GLUED-IN RODS","authors":"А.Ya. Naichuk","doi":"10.31650/2707-3068-2021-25-92-102","DOIUrl":"https://doi.org/10.31650/2707-3068-2021-25-92-102","url":null,"abstract":"In the modern construction of buildings and structures there are many constructive solutions for connecting the rafter with the column of wooden three-hinged portal frames. One of these constructive solutions is the use of knee joints executed as joint on glued-in rods. Despite the accumulated experience in the construction of buildings using timber structures with joints on glued-in rods, there are still urgent tasks to improve the technology of their manufacture and calculation models. The purpose of this work was to conduct experimental and theoretical studies of the knee joint executed as joint on glued-in rods to determine the stress-strain state of the timber in the connection region. To develop of proposals for improving knee joint executed as joint on glued-in rods. The study of the stress-strain state of the knee joint was carried out by solving a plane problem of the theory of elasticity using a software package based on the finite element method. In the software package used, procedures are implemented to take into account the anisotropy of the mechanical properties of wood, the violation of contact between the surfaces of the elements connected in the knee joint. Experimental studies were carried out by the method of static loading of a prototype of a knee joint made in full size, which in its geometric parameters and material properties corresponded to the CE model. As a result of the conducted studies, it was found that in the stretched zone of the knee joint, the glued rods of the rafter and the column are characterized by a significant uneven distribution of forces, in addition, the rods are subjected to compression, tension and bending. The most loaded are the rods located at the maximum distance from the joint of the rafter and the column. The distribution of forces in the rods of the compressed zone is close to uniform. The stress distribution along the length of the inclined rods of the embedded parts is characterized by a large unevenness. Based on the analysis of the stress-strain state of the knee joint of the frame, a new design solution is proposed in terms of the number of glued-in rods and their spacing.","PeriodicalId":365885,"journal":{"name":"Modern structures of metal and wood","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117137436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}