Minimum Material Cost Research Articles

Automated Leadership Selection Educational Projects Based on Genetic Algorithms

Purpose or research.The purpose of the study is to conduct a research of the possibility to use automated methods of finding a solution for the task of forming a selection of candidates in solving a wide range of business problems with the possibility of the influence of such factors as: requirements for the quality of business processes, restrictions on the competence of candidates, the employment of candidates in other processes of the company, planned urgency of fulfilling tasks, the amount of tasks in the pool and expected tasks, tasks characteristics, private policy of the company when selecting candidates, company's policy on risks.Methods.A typology of innovative business tasks is given by the subject area, the range of target results, the duration of execution, etc. External and internal factors are considered to ensure the effective operation of the project team and the success of the project. There are offered sets of attributive characteristics for assessment of projects quality and potential projects. The structure of the algorithm for solving the problem of creating a selection of candidates for solving a set of problems is considered. Prerequisites for using principles of genetic programming in solving the problem under consideration are given. Search algorithm implementation parameters, criteria and constraints are defined. Algorithm was implemented as well as modeling in the Jupyter Lab v2 environment. The results are described in the text. A relative analysis of practical effectiveness of the algorithm was carried out depending on the modeling parameters to justify the selection of their values.Results.The task of creating a selection of candidates for the implementation of projects pool considering a number of factors was described during the study. An approach to solving the problem based on a genetic heuristic search algorithm has been developed. A numerical simulation was performed in Jupyter Lab v2. Simulation results were analyzed, and algorithm parameters were selected.Conclusion.The proposed approach allows not only automatize the selection of managers based on the accumulated data history, but also to adjust the established process to change the vector of organization development. The interaction of education and informatics (information technology) can enrich and expand the field of both sciences in the field of recruitment of innovative project teams. Their object analysis, supplemented by genetic programming capabilities, together allows you to achieve specified qualities of the head of innovative project teams that help maximize business benefits while minimizing material costs. As a result of computational experiments using mathematical apparatus and genetic algorithm technologies, it is necessary to emphasize the possibility of extrapolating such approaches to any level of implementation of innovative projects.

Forecast of mechanical properties of metal products

Introduction. The mechanical properties of the metal depend primarily on their chemical composition and structure. The structure of metal materials is formed under the influence of different temperature modes of manufacture and cooling. Models for predicting the mechanical properties of steels and cast irons are based on the influence of chemical composition and structure. The paper considers an approach that allows to evaluate the mechanical properties of rolling (C) cast iron rolls with a pearlitic (P) matrix depending on the complex influence of the elements of their chemical composition. Materials and methods. The working area of СПХН roll cast iron samples from the surface up to 50 mm doped with chromium (X) and nickel (H) was investigated. The carbide content varied from 10 to 15 %; and lamellar graphite did not exceed 2 %. The results of the experiment. In the work for modeling the mechanical characteristics of cast iron rolls used the method of planning experiments. The choice of this technique is due to the multi-parameter technology of production of solid metal casting. The application of this technique allowed to obtain models for predicting the mechanical characteristics of roll cast iron SPHN depending on the influence of the elements of the chemical composition of the rolls (C, Si, Mn, P, S, Cr, Ni). The error in predicting the tensile strength sВ, bending strength sзгин bending and hardness according to the Shore HSD method did not exceed 5,89 %. When checking the models for convergence of results by Fisher's criterion at a critical value of Fcrit = 2,400 for sВ, this coefficient was 1,249; for sзгин fold was 1,289 and for HSD - 1,012. To analyze the effect of carbon on mechanical characteristics, two-dimensional dependence plots are constructed. Conclusions. Within the operating values of the parameters of the chemical composition of cast iron rolling mills СПХН-45 in accordance with existing regulations, a forecast of their mechanical characteristics within the allowable limits of error of experimental data. The results of the work allow to obtain mathematical models in the process of production of rolls of the СПХН brand to quickly establish their chemical composition within the standard technology in accordance with the customer's requirements for these mechanical characteristics. In addition, the obtained models can predict these characteristics of the manufactured rolls with minimal material and time costs.
 Keywords: rolling mills; elements of chemical composition; mechanical characteristics; multiparameter technology

Mathematical model of forecast of strength of low carbon steel

Introduction. The use of different mathematical approaches to assessing and forecasting the quality characteristics of materials for different purposes is always relevant. The urgency of solving problems and problems of modern materials science with the use of methods of mathematical modeling allows to optimize technological processes of production, to determine in a short period of time the set parameters with minimal time and material costs. In the work using the method of regression analysis, the strength criteria of low-carbon low-alloy steel depending on the characteristics of the structure were evaluated. Materials and methods. Samples of Ст3пс steel grade made of a circle with a diameter of 24 mm were selected as the material for the study. The structure and mechanical properties were investigated at three reference points: at a distance of 0 mm from the center of the sample, 6 mm from the center of the sample and 12 mm from the center of the sample. The steel was investigated in the state of factory delivery, and after two modes of heat treatment to obtain ferritic-perlite and bainite structure. The following properties were determined: microhardness, tensile strength and yield strength, hardness and toughness at room temperature. The results of the experiment. Models for estimating mechanical properties were obtained using regression analysis. Models describing the relationship between the microhardness of pearlite and its area (R2 = 0.8366) in the state of factory delivery have a relatively high correlation coefficient; the score and the ultimate strength (R2 = 1.0) and yield strength (R2 = 0.8669) of steel after cooling in an oil medium; hardness and area of pearlite after hardening steel in the pearlite region (R2 = 0.7215). Conclusions. The practical significance of the work performed is the ability to perform a rapid analysis of the properties of rolled metal from steel Ст3пс based on determining the area of the structural elements and their scoring. However, it should be noted that the existing discrepancy between the results of the experiment and the forecast using the obtained models may be due to the influence of other factors. Such factors include the influence of chemical composition, incompleteness of formal axiomatics, which occurs when estimating the geometry of complex structural elements.
 Keywords: low-alloy steel; structure; chemical composition; mechanical properties; regression model; properties forecast

Nonlinear frequency and chaotic motion of the honeycomb higher-order disk with graphene nanoplatelets face sheets subjected to harmonic excitation via two-dimensional analysis

Honeycomb structures are one type of structure that has the geometry of a honeycomb to allow the minimization of the amount of used material to reach minimal material cost and minimal weight. For this issue, in the current analysis, an attempt is made to develop the nonlinear mathematical model for the chaotic and large-amplitude motions of a sandwich disk with graphene nanoplatelet face sheets honeycomb core and subjected to external excitation. Using Hamilton’s principle, higher-order shear deformation theory (HSDT), and the Von-Karman nonlinear theory, the nonlinear governing equation is derived. The generalized differential quadrature method (GDQM) and perturbation approach (PA) are eventually used to develop a precise solution approach. This article’s fundamental and golden results are that for clamped–clamped boundary conditions, the softening of the system in zone 2 is less than zone 1, whereas the instable responses in zone 2 are more than zone 1. Also, for the sandwich disk with clamped–clamped boundary conditions, the system’s dynamic behavior tends to be more harmonious and less chaotic as the fiber’s angle increases. Therefore, increasing the fiber angle reduces the system’s chaos with clamped edges, which is very important for future works.

Theoretical investigation on the acoustic performance of Helmholtz resonator integrated microperforated panel absorber

Broadband sound absorption at low frequency with minimal space consumption and material cost is a trending research problem in engineering acoustics. Conventional sound absorbers like porous materials and microperforated panels (MPP) are not good enough to absorb sound in the low frequency regime. To enhance the acoustic performance, Helmholtz resonator with inserted neck (HRIN) is integrated with MPP in this investigation. The sound absorption characteristics of series and parallel arrangements of both MPP and multiple HRINs are theoretically modelled using electro-acoustic analogy and the results are compared with full field finite element simulations. Most importantly, it is observed that the parallel arrangement of MPP and multiple HRINs considerably reduced the thickness of the absorber. In addition, a single unit comprising four parallel Helmholtz resonators when arranged in conjunction with MPP absorbed more than 65% sound over a band width of 318 Hz to 880 Hz whereas the successive arrangement of the same unit with MPP is affected with high anti-resonance effect. It is demonstrated that, the proposed modelling strategy very well predicts the acoustic performance of HR integrated MPP absorbers on par with the computational intensive numerical simulations. Moreover, these configurations exhibited efficient low frequency sound absorption capability even with reduced absorber thickness.

СИНТЕЗ АНТИФРИКЦИОННЫХ ПОКРЫТИЙ МЕТОДОМ ФАБО

In the paper, the technology of obtaining antifriction coatings by the method of finishing antifriction-free abrasive treatment with the implementation of the wear-free effect is proposed. (Research purpose) The research purpose is in developing an effective technology for obtaining copper coatings on the surface of steel parts of the shaft type to reduce the wear rate in the conditions of oil starvation of machine parts. (Materials and methods) During the study, a laboratory facility for the synthesis of antifriction coatings on the surface of steel parts by the method of finishing antifriction-free abrasive treatment has been developed. Brass of the LS-59-1 brand was used as a material for applying a copper antifriction coating. In order to activate the surface of the part and the surface of the filler material, a technological medium based on a ten percent solution of hydrochloric acid and glycerol was used. Authors determined the composition of the technological environment empirically. The obtained laboratory samples were subjected to tribological studies in comparison with standard antifriction alloys. X-ray diffraction studies were performed to determine the phase composition. (Results and discussion) As a result of X-ray diffraction studies of laboratory samples, the presence of iron and copper components in the synthesized coating was studied. The content of oxides on the surface of the coating is insignificant, the internal structure is dense with no visible porosity. The coating consists of 95 percent copper, the synthesis process takes place without oxidation, which gives the coating a high adhesive and cohesive strength. The coating thickness is uniform and varies within 3-5 micrometers. (Conclusions) Comparative tribological studies have shown high resistance to wear and to the setting of the contact surfaces under conditions of oil starvation. The coefficient of friction is stable and low and is in the range of 0.08-0.15. The developed technology makes it possible to increase the wear resistance of steel parts of the shaft type in the shortest possible time and with minimal material costs and can be successfully implemented in the conditions of repair enterprises.

Investigation of the pressure and heat treatment effect on the ICE piston blanks mechanical and structural properties from high-strength aluminum alloy B95

The features of the production of internal combustion engine pistons are analysed. On the basis of the analysis, the expediency of developing a new, more improved technology for the production of piston blanks was revealed. The choice was made in favour of the injection molding process. It is shown that the high quality of workpieces with minimal material and energy costs can be ensured by imposing high pressure on the metal prior to crystallization. The scientific and technical literature is analysed, where attention is drawn to the relevance of the processes of processing crystallizing metal by pressure using hydraulic press equipment. However, it can be seen from the available sources that the possibility of pressure treatment of liquid metal prior to the onset of crystallization remains unexplored. Investigations of the mechanical properties of the resulting blanks of internal combustion engine pistons have been carried out, and the microstructures of the alloy obtained under different crimping modes have been studied. As a result of the research, the most optimal technological modes of pressure application were determined. The process of applying pressure to the crystallizing metal has been developed.

Optimization of Metal–Ceramic Functionally Graded Plates Using the Simulated Annealing Algorithm

This work involves the design optimization of metal–ceramic through the thickness of functionally graded material (FGM) plates subjected to thermomechanical loadings. Constrained optimization was performed for minimum mass and minimum material cost of the FGM plates. The design process of FGM plate structures requires a good choice of metal and ceramic materials and the adequate definition of the components volume fractions through the thickness direction in order to accomplish a certain structural behavior, while optimizing the material costs and/or the plate mass. Here, the optimization problems are solved with the simulated annealing (SA) algorithm, not requiring the calculation of the derivatives of the objective or constraint functions. Constrained single objective optimization cases are studied, and validated with alternative solutions, considering the p-index and the FGM plate thickness as design variables. New optimization cases, involving additionally the metal and ceramic materials as design variables, are presented both for benchmark purposes and to demonstrate the suitability of the SA algorithm to solve those optimization problems.

ПОВЕРХНОСТНЫЙ СТОК ТАЛЫХ ВОД НА ПАХОТНЫХ ЗЕМЛЯХ НИЖНЕГО ДОНА

Purpose: to study the indicators of melt water runoff from arable land of various compaction and to assess its quantitative and qualitative characteristics based on long-term data. Materials and methods. Studies of the intensity of melt water runoff were carried out in the Azov zone of Rostov region in the period 1964–2018 by a number of researchers, including the author of the article. Results. The runoff indicators for a 55-year period are characterized by significant fluctuations. Analysis of long-term data revealed that the indicator of melt water runoff rate from loose arable land for the period 1964–2018 averaged 9.0 mm/year and on compacted arable land averaged 17.5 mm/year. On loose arable land, the maximum runoff rate for a 55-year period is 25.3 mm, on compacted arable land it is 47.3 mm. As a result of the analysis of the data, it was revealed that the average water reserve in snow on the surface of the fall-plowed land is 43.7 mm, and 48.7 mm on the winter wheat sowing. In general, for two agrophonies, the runoff indicator for the period 1964–2018 was most often characterized as weak and very weak only on loose arable land. Calculations of statistical indicators of runoff data revealed that they are not uniform, for example, the coefficient of runoff variation from loose arable land was 115.4 %, and from compacted arable land 70.4 %, with a coefficient of variation above 33 %, the aggregate is considered heterogeneous. Rostov region, having a large agricultural potential, is experiencing significant problems from the impact of negative natural processes, among which one of the first places belongs to erosion processes. Conclusions. In the course of generalization of long-term data on melt water runoff from arable land of varying degrees of compaction, indicators that made it possible to plot the flow availability curves were obtained. The use of the results obtained makes it possible to predict the occurrence of runoff of various intensities and thereby prevent its negative impact on agricultural land with the minimal material costs.

СИНТЕЗ АНТИФРИКЦИОННЫХ ПОКРЫТИЙ МЕТОДОМ ФАБО

In the paper, the technology of obtaining antifriction coatings by the method of finishing antifriction-free abrasive treatment with the implementation of the wear-free effect is proposed. (Research purpose) The research purpose is in developing an effective technology for obtaining copper coatings on the surface of steel parts of the shaft type to reduce the wear rate in the conditions of oil starvation of machine parts. (Materials and methods) During the study, a laboratory facility for the synthesis of antifriction coatings on the surface of steel parts by the method of finishing antifriction-free abrasive treatment has been developed. Brass of the LS-59-1 brand was used as a material for applying a copper antifriction coating. In order to activate the surface of the part and the surface of the filler material, a technological medium based on a ten percent solution of hydrochloric acid and glycerol was used. Authors determined the composition of the technological environment empirically. The obtained laboratory samples were subjected to tribological studies in comparison with standard antifriction alloys. X-ray diffraction studies were performed to determine the phase composition. (Results and discussion) As a result of X-ray diffraction studies of laboratory samples, the presence of iron and copper components in the synthesized coating was studied. The content of oxides on the surface of the coating is insignificant, the internal structure is dense with no visible porosity. The coating consists of 95 percent copper, the synthesis process takes place without oxidation, which gives the coating a high adhesive and cohesive strength. The coating thickness is uniform and varies within 3-5 micrometers. (Conclusions) Comparative tribological studies have shown high resistance to wear and to the setting of the contact surfaces under conditions of oil starvation. The coefficient of friction is stable and low and is in the range of 0.08-0.15. The developed technology makes it possible to increase the wear resistance of steel parts of the shaft type in the shortest possible time and with minimal material costs and can be successfully implemented in the conditions of repair enterprises.

Design and Optimization of 200 Ton H- Type Hydraulic Press

A hydraulic press is a machine using a hydraulic cylinder to generate a compressive force. The hydraulic press works on Pascal’s principle, which states that the pressure throughout a closed system is constant. Hydraulic presses are commonly used for forging, clinching, moulding, blanking, punching, deep drawings and metal forming operations.200-ton capacity hydraulic frame and cylinder are modelled using Solidworks and analysed by solidworks simulation using finite element analysis. The objective of the project is to optimize the total mass and cost of hydraulic press while assuring adequate stiffness by using honeycomb structure on ram. Honey comb structures allows the minimization of material used to reach minimal weight and minimal material cost by providing high strength without compromising the output quality.

Разработка комплексного подхода к дизайну текстильных средств реабилитации для детей

This paper reviews the characteristics of emergence formation and development of the Inclusive Design field. As it points out year after year the number of children with health disabilities is increasing, unfortunately. The research has shown that various rehabilitation tools should be developed for disabled children's more successful socialization, development and education. The authors suggests the technical means of rehabilitation classification based on the main material of manufacturing, which includes textile means of rehabilitation. Textile means of rehabilitation are an extensive list of products, comprising inclusive and rehabilitation clothing, technical equipment (for example, fixers for sedentary and bed patients of various purposes) also developing educational aids, as well as textile developing educational toys. Textile materials are differentiated by raw material composition, texture, physical properties, color scheme. This variety allows quick and convenient creation of various rehabilitation means with minimal material costs. Additional multifactorial capabilities are provided by the fact that products can be made from combinations of different textile materials, as well as complement products from other materials. Methods (transformations, combinatorics, etc.) and principles (adaptability, etc.) are defined, which contribute to solving certain problems of designing textile rehabilitation means. The paper comes up with an integrated approach to the design of such rehabilitation devices, which will allow designing products that have the greatest rehabilitation effectiveness. The authors also provide the classification of textile means of rehabilitation on a basis of purpose.

УСТАНОВКА ДЛЯ ФИЗИЧЕСКОГО МОДЕЛИРОВАНИЯ ПРОМЫВКИ ЗАСОЛЕННЫХ ПОЧВ

Gradients of salts concentrations of the soil solution, rinsing water pressures, filtration coefficients determine the flow intensity of the salt solutions in the aeration zone. There are known a lot of software for calculating the motion of salt solutions in the porous medium. To assess the accuracy of calculations of the salts movement in the soil, the data of gradient measurements are used. The implementation of the known methods of physical modeling on the soil monoliths mounted according to Astapov, lysimetric installations, in experimental leaching of saline soils in the field requires significant material investments, labor and time. Minimum material and labor costs are required for the assembly and use of the proposed design of the installation for physical modeling of saline soil washing. A working prototype of the installation has been developed. It includes piezometers, a case, units of piezometers connection, sampling of soil moisture combined with soil electrodes, equalizing drain, rotating part of the case. Piezometers, drains and connecting hoses, soil moisture sampling unit. The installation case is assembled of separate branch pipes equipped with necks and sealing rings. Filtration investigations and gradient measurements of the salts movement are carried out on the installation. The tests of the installation prototype were fulfilled in the field on the sand pit reclamation map located in the floodplain of the Gzhelka and Moskva rivers of the Ramensk region of the Moscow area. The profile filtration coefficients measured at the installation – 2.33 ± 0.031 m / day and in the field conditions – 2.36 ± 0.041 m / day do not differ significantly.

НАУЧНО-ИССЛЕДОВАТЕЛЬСКИЕ ИСПЫТАНИЯ ГАЗОГЕНЕРАТОРА ПЕРСПЕКТИВНОГО ДВУХКОНТУРНОГО ТУРБОРЕАКТИВНОГО ДВИГАТЕЛЯ С ИМИТАЦИЕЙ ТРЕБУЕМЫХ ВХОДНЫХ ТЕРМОГАЗОДИНАМИЧЕСКИХ ПАРАМЕТРОВ В УСЛОВИЯХ МОТОРОСТРОИТЕЛЬНОГО ПРЕДПРИЯТИЯ

The method of advanced bypass turbojet engine core research tests with simulation of target inlet thermogasdynamic parameters at the engine OEM site is considered. It is stated that research testing is traditionally associated with the use of multifunctional test facilities capable of simulat-ing operating conditions as close as possible to operational ones for a wide range of test objects of different thrust (power) and application. Such test facilities require significant investment and operating costs, which in general determines their limited number in the world. It is shown that the steady growth of the share of research tests at the initial design stages requires organization of tests with minimal financial and material costs directly at the engine OEM site, where testing the advanced bypass turbojet engine core plays a special part. Determination of the method for simulating thermogasdynamic parameters is associated with solution of rather contradictory problems, where, on the one hand, it is required to ensure reliable reproduction of the actual operating conditions of the core for all configurations of the bypass turbojet engine under development, and on the other hand, to ensure lower manpower and cost of testing. One of the effective solutions is the use of specialized test facilities, a distinctive feature of which is determination of the simplest and most economical means of obtaining the working fluid with the required thermogasdynamic parameters for a pre-determined range of test objects of different thrust (power) and application. The technical implementation of the dedicated test facility for testing the advanced bypass turbojet engine core at UEC-Aviadvigatel JSC (Perm) is considered.

НАЛОГОВЫЕ ИНСТРУМЕНТЫ ДЕОФШОРИЗАЦИИ РОССИЙСКОЙ ЭКОНОМИКИ НА СОВРЕМЕННОМ ЭТАПЕ

The article highlights the main trends in the policy of de-offshorization of the Russian economy at the present stage on the basis of a comprehensive analysis of the legal prescrip-tions of international legal acts and national tax legislation The article formulates and describes the system of tax and legal instruments for de-offshorization in the context of the development of the best national and foreign practices, as well as the theoretical views of scientists and is considering the problems and prospects of the implementation of each tool. The shortcomings and contradictions of regulations in the studied area are highlighted. The goals of state policy in the area of economic security of the Russian Federation in-clude the following: strengthening economic sovereignty, ensuring economic progress and increasing sustainability of the economy to external and internal threats. In the context of the above mentioned goals, the state defines for itself the main tasks, calculated for a long period of time, which are designed to facilitate the process of de-offshorization. The essence of de-offshorization should be comprehensively considered from the stand-point of international and domestic legislative regulation. The experience of generalizing the best foreign and national practices, theoretical views of scientists allows us to highlight the most effective set of financial and legal instruments for implementing the mechanism of de-offshorization of the Russian economy at the present stage. It seems possible to group the main trends in tax regulation in this area as follows. First, the modernization of some intergovernmental agreements and conventions of the foreign eco-nomic nature on the double tax avoidance on income and capital and on the prevention of tax evasion on income. In the second place, amendments to the domestic tax legislation in terms of determining CFC profits, simplifying tax administration, determining the procedure for conducting mutual agreement procedures, limiting mechanisms for reducing the tax burden (simplified limitation of benefits, S-LOB). Third, the expansion of the international institution for the international automatic exchange of financial information. This method of interaction between tax administrations of states allows to achieve the goal of reducing the shadow economy by increasing the transparency of infor-mation on taxpayers' accounts with minimal time, material and organizational costs. The de-offshorization policy is currently yielding the expected results. The main achievements in this field include the digitalization of information data about the taxpayer, as well as the creation of a legal, organizational, technical and methodological platform for the automatic exchange of such information between public authorities within the country and with opposing states.

Моделирование резания грунта при различных углах атаки лемеха рабочего органа стоечного рыхлителя методами фрактального анализа

The level of soil compaction is influenced by physical and mechanical properties, climatic conditions, the amount of annual precipitation, the type of cultivated crops, and other factors. Excessive compaction of the soil impairs water permeability and air access to the roots, resulting in reduced crop yields, increased soil erosion, reduced fertilizer efficiency, which leads to an increase in the cost of material and technical resources for tillage. Therefore, it is important to solve this problem with minimal energy and material costs. Such a solution is the loosening of the soil, which can be done naturally and with the help of mechanical loosening. (Research purpose) The research purpose is in evaluating the effectiveness of loosening the soil with a U-shaped ripper at different angles of the ploughshare using fractal analysis methods, which is necessary to reduce additional loads during further soil treatment. (Materials and methods) A dirt channel with a special cart was used to consider physical models of meliorative machines and specialized working equipment. (Results and discussion) Author conducted six experiments in a soil tray for each corner of the ploughshare separately. Nineteen ground sections were made. The structure of the soil before and after treatment depends on the mode of operation of the ripper model and the design features of its working bodies. (Conclusions) The more energy is spent on the treatment of homogeneous areas, the more the soil structure changes. To quantify the structural changes in the nature of the cultivated soil, we used its fractal characteristics, in particular, the fractal dimension. The soil sections have fractal properties, and, accordingly, fractal methods can be used for their analysis. The article proves the applicability of fractal methods in the analysis of the quality of tillage and the degree of its loosening.

Cable optimization of a cable-stayed bridge based on genetic algorithms and the influence matrix method

Structural optimization is an important tool for structural designers that helps them to find innovative design solutions and structural forms with a better exploitation of materials as well as decreased self-weight and minimum material costs. In this article, a design procedure coupling the influence matrix method and genetic algorithms to optimize stay cables in cable-stayed bridges is presented. Following that, the design procedure is utilized in the preliminary design of a twin towers double-cable planes cable-stayed bridge to be located in Ferrara, Italy. The cable cross-sectional areas and corresponding pre-tension forces are optimized simultaneously. The results demonstrate that the proposed procedure is a powerful tool for designing stay cables and predicting the optimum cross-sectional areas of stay cables under certain stress and displacement constraints.

Efficient storey lateral stiffness estimate and gradient-based multi-objective optimization of reinforced concrete frames with hybrid semi-rigid precast connections

By fully utilizing the designability of semi-rigid connections in precast concrete structures, the gradient-based interior point algorithm is applied to perform a two-stage optimization with the objectives of minimum material cost and a target interstorey drift ratio distribution. To obtain an efficient storey lateral stiffness estimate for optimization, the modified Muto’s method is further extended to address hybrid distributions of connections. Based on the characteristics of the modified Muto’s method, the dual objectives of attaining the target interstorey drift ratio distribution and minimizing the material cost are treated as two separate objectives in the optimization. A case study on precast concrete frames with different storeys, connection parameters and target interstorey drift ratio distribution patterns demonstrates the efficiency and accuracy of the proposed approach. Such an approach could be suitable for the preliminary design of precast concrete structures with hybrid semi-rigid connections.

Carbon and Cost Optimisation and Visualisation

We have developed a Grasshopper script that designs carbon-cost optimised foundation slabs to demonstrate the potency of parametric design in AEC, particularly the fact that environmentally friendlier solutions can be designed without having to cost more. The script produces 3D models of foundation slabs with minimal carbon footprint and material costs and validates each design iteration from the structural point of view with respect to project specific inputs, such as materials, cost, forces and bearing capacity of the ground. The script has been tested in a multitude of input settings and in all cases returned design solutions for foundations slabs where it was possible to identify the least climate intensive design to also be one of the cheapest solutions, if not the cheapest solution. We have developed a new service called BIM Vision to apply value driven visualisations based on carbon footprint and costs in BIM models. The result of this service is a further developed BIM model which integrates emission and cost factors with individual 3D objects. On demand, a user of the BIM model can also produce climate and cost calculations and visualise the BIM model based on the chosen sustainability aspect. Using a colour palette generator, objects are coloured with respect to carbon and cost intensity. Thus, a 3D heat map of the BIM model is created to communicate intuitively what components have the most severe impact on the project budget and carbon footprint. This kind of communication of environmental aspects simplifies consumption of sustainability related data and make it actionable.

Frequency simulation of viscoelastic multi-phase reinforced fully symmetric systems

Honeycomb structures have the geometry of the lattice network to allow the minimization of the amount of used material to reach minimal material cost and minimal weight. In this regard, this article deals with the frequency analysis of imperfect honeycomb core sandwich disk with multiscale hybrid nanocomposite (MHC) face sheets rested on an elastic foundation. The honeycomb core is made of aluminum due to its low weight and high stiffness. The rule of the mixture and modified Halpin–Tsai model are engaged to provide the effective material constant of the composite layers. By employing Hamilton’s principle, the governing equations of the structure are derived and solved with the aid of the generalized differential quadrature method (GDQM). Afterward, a parametric study is done to present the effects of the orientation of fibers ( $$\theta_{{\text{f}}} /\pi$$ ) in the epoxy matrix, Winkler–Pasternak constants ( $$K_{{\text{w}}}$$ and $$K_{{\text{p}}}$$ ), thickness to length ratio of the honeycomb network ( $$t_{{\text{h}}} /l_{{\text{h}}}$$ ), the weight fraction of CNTs, value fraction of carbon fibers, angle of honeycomb networks, and inner to outer radius ratio on the frequency of the sandwich disk. The results show that it is true that the roles of $$K_{{\text{w}}}$$ and $$K_{{\text{p}}}$$ are the same as an enhancement, but the impact of $$K_{{\text{w}}}$$ could be much more considerable than the effect of $$K_{{\text{p}}}$$ on the stability of the structure. Additionally, when the angle of the fibers is close to the horizon, the frequency of the system improves.