Efficient Use Of Materials Research Articles

Detail categories for the flange-to-web weld detail in corrugated web girders

Corrugated web girders have gained popularity in both buildings and bridges due to their efficient use of materials. Previous research work has demonstrated that stainless steel corrugated web offers a promising solution for composite road bridges. However, to utilize these girders Efficiently in bridges, it is crucial to understand their fatigue performance. Notably, EN1993–1-9 does not include a detail category for the flange-to-web weld detail in girders with corrugated webs made of either carbon or stainless steel. To address this gap, numerous tests have been conducted and reported in the literature on carbon steel girders with various corrugation geometries. This paper aims at deriving detail categories for the flange-to-web weld detail in girders with corrugated webs. As a first step, it focuses on carbon steel, compiling, analyzing, and evaluating 86 fatigue test results available in the literature. The results show that the corrugation angle is the most important geometric parameter influencing the fatigue strength of the studied details. Based on this work, the following detail categories are proposed for various corrugation angles: DC125 for angles smaller than 30°, DC112 for angles between 30° and 40°, DC100 for angles between 40° and 45°, and DC90 for angles between 45° and 60°. Furthermore, the impact of other influencing geometrical parameters, such as bend radius and flange thickness, on fatigue strength is explored. The risk for root cracking in the weld between the flange and corrugated web is also evaluated through effective notch stress analysis.

Miniaturized Shear Testing: In-Plane and Through-Thickness Characterization of Plywood.

This study addresses the challenges associated with conventional plywood shear testing by introducing a novel miniaturized shear test method. This approach utilizes a controlled router toolpath for precise sample fabrication, enabling efficient material use and data acquisition. Miniaturized samples, designed with double shear zones, were tested for τxy, τxz, and τyz configurations using a universal testing machine. Results revealed a mean ultimate shear strength ranging from 5.6 MPa to 7.3 MPa and a mean shear modulus ranging from 0.039 GPa to 0.095 GPa, confirming the orthotropic nature of plywood. The resulting shear behavior was determined with stress-strain curves correlated with failure patterns. The miniaturized tests effectively captured the material's heterogeneous behavior, particularly at smaller scales, and demonstrated consistent load-bearing capacity even after substantial stress reduction, suggesting suitability for bracing applications. This method allows for increased sample sizes, facilitating robust data collection for developing and validating finite element models. Future work will focus on evaluating the scalability of the observed orthotropic behavior and data scatter at larger scales and assessing the potential for this method to replace conventional full-scale plywood shear testing.

Predicting fatigue crack initiation life in typical joints of offshore observation tower structures

ABSTRACT Tubular structures are widely used in steel constructions, such as offshore platforms, because of their superior mechanical qualities, efficient use of materials, lightweight and aesthetically pleasing appearance. The most common failure mode of offshore tubular joints is fatigue damage brought on by cyclic loading during the course of their service life, like wind, wave and equipment vibration. In this paper, the finite element model of the TK-type tubular joint at the stress concentration position is established by analyzing the load and response of the observation tower. The continuum damage mechanics method has been used to evaluate the fatigue crack initiation position and life of the tubular joint, and the crack initiation life of the key nodes has been predicted, which provides theoretical support for ensuring the service safety of the offshore observation tower.

ЄВРОІНТЕГРАЦІЙНІ ІМПЕРАТИВИ ПОВОЄННОГО ВІДНОВЛЕННЯ УКРАЇНИ НА ЗАСАДАХ СТАЛОСТІ: У ПОШУКАХ ДЖЕРЕЛ ФІНАНСУВАННЯ

The purpose of the article is to study the specifics of financing investment projects on the principles of sustainability and circularity, the demand for which will grow in the conditions of post-war reconstruction of Ukraine, which will take place taking into account the European integration imperatives of the international economic policy of Ukraine. It is proven that “sustainability” is a kind of framework concept that simultaneously imposes restrictions and creates opportunities for attracting capital. In the conditions of post-war reconstruction of Ukraine, it becomes promising to increase in the portfolio of investment projects those that are oriented towards the implementation of circular business models that serve as a tool for implementing green and circular transitions. Revision of value and supply chains taking into account the “dominant of circularity” is an imperative of the “green” European integration course.The circular economic model is an innovative platform and ensures sustainable development by moving from a linear model based on consumption and recycling to one in which the service life of products is maximized, natural resources are reused, and materials and waste are minimized. Currently, three distinct cycles of circularity are distinguished, which are gradually becoming wider: closing resource cycles, which is determined by the relatively traditional economic system; slowing down resource cycles and material flows through the continuation and intensification of the use of products to preserve their value and cost over time; narrowing resource cycles through more efficient use of materials, resources and products of the linear system. The transformation processes taking place in the financial sector under the influence of the greening of financial policies not only of companies, but also of the Central Banks of the leading countries of the world, show that ignoring the sustainability factor and non-compliance with ESG criteria will affect the credit ratings of institutions in particular and reputational positions in general. “Green” factors increasingly aggressively determine the ability of small and medium-sized enterprises (SMEs) to apply for grant support for financial provision of circular and sustainable projects. Circular, green and energy transitions in the context of sustainable development will act as a universal tool for achieving many Sustainable Development Goals (SDGs), which will make it possible to attract financial resources from special funds that deal with solving global development problems. Europe strives to become the world's first climate-neutral continent by 2050. The EU must transform into a fair and prosperous society with a modern and competitive economy. This highlights the need for a holistic and cross-sectoral approach, in which all relevant policy areas contribute to achieving the ultimate climate-related goal. The implementation of environmental initiatives at the global, regional, inter-country and macro-, meso-, micro-levels is facilitated by political initiatives of actors at the global, regional and national levels. Therefore, The European Union (EU), having adopted ambitious goals of achieving climate neutrality, uses the European Green Deal, which is fundamentally capable of modifying the investment and financial landscape, which should be taken into account when selecting investment projects within the framework of post-war reconstruction programs. In the process of post-war reconstruction of regions, the challenges of solving the problems of energy security, resource security, water resources management will be on the agenda. Ukraine during the post-war development has all the prerequisites for acquiring the status of a green and circular center of Europe. In the context of decentralization, the coordination of relevant initiatives becomes significantly more complicated: on the one hand, the liberalization of the institutional space provides a lot of flexibility to municipalities and communities, on the other hand, post-war socio-economic development creates a demand for strategic planning of Ukraine's place in the international division of labor, and therefore - strategizing its industrial development on the basis of sustainability. Under these conditions, the European Green Deal can become a kind of strategic framework that will clearly define the standards for greening business principles. It is fully foreseen that attracting financing from EU funds will involve increasing requirements for corporate social responsibility of enterprises.

Innovative applications for civil structures of the Municipality of Finiq using topology optimization and additive manufacturing

The Municipality of Finiq is located in the South of Albania, inside the Vlora’s County and it is just 9 kilometers from the City of Saranda. The village of Finiq is particularly important because of the presence of The Archaeological Park at the top of the hill, which has received this status in 2005. Inside the Municipality there are a lot of attractive sites, such as The Blue Eye, the main lake of the Municipality, the Monastery of St. Nikolla, located in Mesopotam, etc., making the Municipality dominated by nature (e.g. long lots of fields, hills, rivers, and lakes) and monuments that represent the cultural heritage of the municipality. Within this context some villages arise, which are characterized mostly by infrastructures and civil structures in reinforced concrete, this is strictly due to the fact that these buildings were built in the last decades, instead of what can be observed outside the Municipality, e.g. Gjirokaster. The structures of the Municipality’s villages are mostly under construction, some are unfinished, abandoned, or damaged. Despite the trend of reinforced concrete building construction does not tend to decrease, the world of civil engineering is trying to find new solutions, that are also environmentally compatible and sustainable. This necessity is motivated by the fact that the industry of concrete is the most energy-intensive industry in the world. In particular, two main aspects that the research is investigating to address these issues are the use of new manufacturing technologies, e.g. 3D printing, combined also with new computational methodologies, such as topology optimization, and the development of innovative materials, e.g. architected meta-materials. The aim of this paper is to suggest innovative approaches and methodologies in the fields of structural mechanics for civil structures. The proposed approach wants to be applied not only to buildings under construction but also to the existing ones, which could be restored or completed in some specific structural and non-structural parts. In particular, we propose new topology optimization strategies that allow us to obtain an efficient material layout with maximized performance under predefined constraints. This design method is not only used to optimize the structural behavior of the structures but also for the optimization of specific features of the structures, e.g. thermal and acoustic optimization. The interest in this computa- tional method has grown due to the development of innovative techniques of manufacturing, i.e. additive manufacturing. In particular, there are different types of manufacturing that could be used for construction, which differ with respect to the material adopted, e.g. steel, concrete, or stone-like materials. The proposed method will be supported by several examples to under- stand the potentiality of the approach considering the role of additive manufacturing. Indeed, the development of new manufacturing methods has reduced the distance between the Theoretical and practical representation of the optimized layout. In conclusion, the proposed approach allows to obtain novel 3D printable structures characterized by a more efficient use of material, contributing to the realization of the concept of circular economy within the construction industry.

Innovation and Digital Transformation in the Business Environment: A Case Study on Analyzing the Impact on Organizational Performance in a CAD Company

Abstract This article makes an exploratory attempt to study the impact of implementing a computer-aided design (CAD) system on a Romanian company. The firm has been established in 1998 and it is based on Baia Mare (Maramures), Romania. It is the commercial administrator of the CAD/CAM Technology Support Center. This center was a project initiated within the Maramureş Center for the Development of Small and Medium Enterprises (SMEs), and it received funding from the PHARE FIDEL program, an European Funded program that supported at that time the development of SMEs). Using a multifaced approach encompassing semi-structural interviews and financial analysis data, the results show integration of innovative CAD technologies yields substantial gains for operational efficiency. For instance, most of the KPIs associated with production have improved: the time required to complete one cycle of production has decreased by 15%, from an average of 20 hours to 17 hours per unit and the efficient use of materials has increased by 10% resulting in cost savings. This research shows how Romanian companies can adopt CAD technologies and improve their activities.

The Effect of Different Curing Temperatures on Properties of Reactive Powder Concrete Reinforced by Micro Steel Fibers

Reactive Powder Concrete (RPC) is a type of high-performance concrete that is known for its exceptional strength and durability also RPC is one of the new composite materials that allow for the most efficient use of materials, which benefits the concrete industry economically. Additionally, it improves environmental sensitivity. The main objective of this paper is the determine some characteristics of RPC, such as (compressive strength and fresh density) after exposure to different curing temperatures (60, 120, and 200) oC for 4 hours due two days. This study involves many variables such as micro steel fibers content with 1% by vol. of reactive powder concrete samples as well as elevated temperature. It was discovered that the optimum temperature that was used after conducting the tests was 60 Celsius, as it gave the best results for the mechanical properties of RPC, which were adopted in the rest of the tests. The value of fresh density increased by about (1.95%) and compressive strength increased by about (33.3%) at 60 oC for the age of 28 days in contrast to the reference mixture.

Policy for material efficiency in homes and cars: Enabling new climate change mitigation strategies

AbstractMaterial efficiency (ME), making products with less material or substituting with less carbon‐intensive material without a loss of functionality, can reduce greenhouse gas (GHG) emissions and complement other strategies to mitigate climate change. Seven ME strategies for cars and homes in the G7 countries were recently modeled in a study by the International Resource Panel. Modeling indicates that ME strategies focusing on construction and use of homes could lower the overall cumulative emissions in the G7 between 2016 and 2060 by 8.5 Gt CO2e (20%), while ME strategies for the production and use of cars could reduce up to 12 Gt (24%). For both homes and cars, the strategy of more intensive use—where fewer or smaller products are required to provide the same basic service—showed the greatest potential. A review of existing ME policies reveals that attention to ME in climate policy has been limited. Policy toward ME has historically focused on waste management rather than GHG reduction. Ex post evaluation of policies that do exist, especially for recycling and related waste strategies, is infrequent. Framing efficient use of materials as a measure primarily intended for climate mitigation is relatively recent and uncommon. Production‐related policy opportunities have been neglected because using ME to reduce GHGs is novel in some sectors and because increased ME faces economic and social barriers. Rebound effects where reduction of the cost of housing or transportation can increase material consumption offsetting potential gains, a problem for all efficiency‐based approaches, is understudied and not currently addressed through policy.This article is categorized under: The Carbon Economy and Climate Mitigation > Policies, Instruments, Lifestyles, Behavior The Carbon Economy and Climate Mitigation > Decarbonizing Energy and/or Reducing Demand

Experimental evaluation of mechanical compression of lattice trusses made with Ti6Al4V for aerospace use

Lattice structures are three-dimensional structures composed of repeated geometrical shapes with multiple interconnected nodes, providing high strength-to-weight ratios, customizable properties, and efficient use of materials. A smart use of materials leads to reduced fuel consumption and lower operating costs, making them highly desirable for aircraft manufacturers. Furthermore, the customizable properties of lattice structures allow for tailoring to specific design requirements, leading to improved performance and safety for aircraft. These advantages make lattice structures an important focus for research and development in the aviation industry. This paper presents an experimental evaluation of the mechanical compression properties of lattice trusses made with Ti6Al4V, designed for use in an anti-ice system. The truss structures were manufactured using additive manufacturing techniques and tested under compressive loads to determine mechanical properties. Results showed that lattice trusses exhibited high levels of compressive strength, making them suitable for use in applications where mechanical resistance and durability are critical, such as in anti-ice systems. We also highlight the potential of additive manufacturing techniques for the fabrication of lattice trusses with tailored mechanical properties. The study provides valuable insights into the mechanical behavior of Ti6Al4V lattice trusses and their potential applications in anti-ice systems, as well as other areas where high strength-to-weight ratios are required. The results of this research contribute to the development of lightweight, efficient, and durable anti-ice systems for use in aviation and other industries.

Effect of tools rotational speed on the mechanical properties of one-step double-acting friction stir welded aluminum alloy AA 6061 hollow panel

The utilization of Aluminum hollow panels enhances structural strength while simultaneously ensuring a lightweight and efficient use of materials. During their application, these panels necessitate a welding process that is susceptible to porosity due to the disparity in hydrogen gas solubility between liquid and solid aluminum. Solid-state welding techniques, such as Friction Stir Welding (FSW), have proven to be effective and appropriate solutions for overcoming this issue. However, due to the thickness of the hollow panels, FSW process is unfeasible as it requires welding on both sides, resulting in prolonged production times. Consequently, the development of a one-step double-acting FSW technique becomes necessary, involving the simultaneous utilization of two tools. The usage of two tools introduces two sources of friction-stir forces, heat, and axial forces, demanding an assessment of the novel response from the specimens. This research aims to analyze the effect of a specific parameter, namely the tool rotation speed, within the one-step double-acting FSW process on the physical and mechanical properties of the AA6061 hollow panels. The One-Step Double-Acting FSW process involved conducting variations in the tool rotation speed on both sides of the welds. Specifically, for the 4G weld position (underside of the workpiece with an overhead weld position), speeds of 1200, 1500, and 1800 rpm were employed. Meanwhile, a consistent rotation speed of 1500 rpm was maintained for the 1G weld position (overside of the material with a flat weld position). The transverse speed and tilt angle are set at 30 mm/min and 2°, respectively. Elevating the tool rotation speed results in increased hardness, load capacity, and bending strength of the weld joints. The specimen subjected to the highest rotational speed (1800 rpm) exhibits the most exceptional mechanical properties, including a hardness of 73.46 HVN, load capacity of 18.47 kN, and bending strength of 60.56 MPa.

Уголковые подпорные стены с вертикальными консолями в виде оболочек и складок

The subject of the study is reinforced concrete corner retaining walls, widely used in hydraulic engineering construction. Optimization of the shape of the vertical console of corner retaining walls is important to reduce internal forces and increase the stability of structures. When replacing flat panels with spatial structures in the console, bending moments are reduced; the predominant work of structures for compression or stretching allows reducing their thickness due to more efficient use of materials. The purpose of the study is to determine the optimal shape and nature of reinforcement of vertical retaining wall consoles, depending on their height. The study was conducted in the certified software package “LIRA-CAD2021”. Computational models of corner retaining walls with consoles in the form of multi-wave cylindrical shells and folds have been developed. At the junctions of the waves and the edges of the folds, racks are provided, pinched in the ground. Comparative calculations of structures in the software package “LIRA-CAD2021” were performed. The results of calculations are analyzed. Conclusions are drawn on the optimization of the structures of retaining walls with a vertical console in the form of shells and folds. The study showed that with a retaining wall height of up to 3 m, a retaining wall with a console in the form of a multi-wave shell is more rational in terms of material consumption. At a height of more than 3 m, retaining walls with a console in the form of folds with vertical posts at the interface of the faces become rational. For consoles in the form of shells, double reinforcement is recommended with an increase in the area of the reinforcement in the lower part and at the interface areas of adjacent waves. For consoles in the form of folds, double reinforcement is also recommended, but additional reinforcement is required only in the area of the interface of the panels with the foundation plate.

ВИЗНАЧЕННЯ ПОКАЗНИКА ЦИРКУЛЯРНОСТІ В ЛІСОВОМУ СЕКТОРІ ЗА ПРИНЦИПАМИ ЦИРКУЛЯРНОЇ ЕКОНОМІКИ

It is substantiated that the implementation of the circular economy in the forest sector is important and relevant, as it helps to preserve forest resources, contributing to the efficient use of materials and the reduction of wood residues, as well as the restoration and reuse of wood products. Analyzed and ranked according to the degree of importance of the principles of the hierarchy of 10R strategies of the circular economy in the forest sector in the form of a watering can, where the upper levels have a higher priority compared to the lower ones. The percentage of importance of each strategy according to the priority of actions of 10R strategies to achieve maximum circularity and sustainability was determined, in particular: Refuse (18.72%); Rethink (17.05%); Reduce (15.05%); Reuse (13.05); Repair (11.04%); Repurpose (9.03%); Remanufacturing (7.03%); Refurbish (5.02%); Recycle (3.01%); Recover (1.00%); Dispose (0.00 %). The state of the circular economy in the processes of logging, production of products from primary raw materials and processing of used (consumed) wood products in Ukraine was analyzed, which made it possible to determine the indicator of circularity in the forest sector. The method of determining the circularity index according to the 10R strategies of the circular economy for the three main components of the forest sector with the formation of three possible growth scenarios has been developed. The indicators of circularity for scenario No. 1 were determined, which characterize the 1st lowest level of efficiency for traditional technologies of utilization and useful use of wood resources with values for the processes: logging 6.02%, manufacturing of wood products 10.03%, processing of used wood 25, 09% Circularity indicators are calculated for scenario No. 2, which characterizes the 2nd middle level of efficiency, with emphasis on advanced technologies and business models based on the extension of the service life and life cycle of products with values for the processes: logging 26.09%, manufacturing of wood products 43.14%, processing of used wood 61.71%. Circularity indicators were calculated for scenario No. 3, characterizing a developed circular economy – the 3rd maximum level of efficiency, built on smart production and smart consumption with values for the processes: logging 43.15%, manufacturing of wood products 76.24%, recycling of used wood 93.15%. Possible weighted average indicators of circularity according to three scenarios were determined: No. 1, which characterizes the situation in the forest sector of Ukraine and is 13.71%; No. 2, which predicts the situation in the forest sector of Ukraine in the next 10-15 years at the level of 43.65%; No. 3, which predicts the situation in the forest sector of Ukraine in the perspective of 2050 at the level of 70.85%. Ways to increase the circularity index in the forest sector based on the principles of the circular economy, which include minimizing waste, optimizing the use of resources, and preserving natural capital, are outlined.

Analysis of Value-Creating and Supporting Component of the Value Chain in the Production Process

This research focuses on the application of the Process Value Added (PVA) method in the environment of custom piece production at STS Prachatice a.s. The main objective was to identify the most profitable and most loss-making processes, to evaluate the value added of individual production operations, to assess the potential for outsourcing certain processes, and to analyse the profitability of specific orders. The study uses a selection of 30 atypical orders from 2022, obtaining data on selling prices, production hours and costs associated with production and overhead. The analysis shows that manufacturing processes add the most value, while inspection processes are less profitable. Processes suitable for outsourcing were identified, especially when in-house capacity is not used. It was also found that the most profitable orders are those that combine high product uniqueness with efficient use of materials and production hours. The PVA methodology allowed to quantify the added value in the context of time and cost parameters and revealed that contracts with high time pool and unit costs have the most significant added value. PVA indices were established to better reflect the results achieved. The research findings have practical implications for the organization and efficiency of the production process at STS Prachatice, contribute to the development of business policy and procurement activities, and serve as innovative material for academic purposes. The study demonstrates that the PVA method is an effective tool for analysing and optimising business processes, enabling companies to better understand and manage process value-added in order to increase profitability and competitiveness. The implementation of this method in practice has shown concrete economic benefits and provided valuable information for further business policy and procurement solutions.

Efficient design of overlapped purlins loaded by gravity

Cold-formed steel represents a competitive solution for a wide range of structural applications due to its efficient use of material and its rapid manufacturing and installation. Concerning the purlin systems, continuous Z-shaped steel purlins overlapping over the intermediate rafters are the best choice to minimise material use. The connection between two purlin segments can be achieved by overlapping the profiles over the supports. Using a finite element model validated against experimental data, an extensive study was performed to identify the parameters that influence the design of overlapped purlins loaded by gravity. The analysis is performed on a two-span continuous beam under gravity loading. To capture as much as possible the real behaviour of the purlin, the sheeting is included in the model. The design of lapped purlins was found to be primarily influenced by the length of the span and the overlap length. The detail of the lapped connection is relevant only for short overlaps. A material efficiency study was performed to determine how the overlapped purlin should be designed to minimise material use. Numerical results demonstrate that short overlaps behave poorly from a material efficiency point of view. The optimal overlap length Lp1 + Lp2 was found to be between 15 and 25 % of the length of the span. Connection details or the use of unsymmetric overlaps do not bring a significant increase in terms of material efficiency. However, the use of higher-grade steels bring great improvements.

Exploring the three-dimensional space with modular concrete shells: Form-finding, design and structural analysis

Thin concrete shells can span large distances thanks to their structural efficiency, following the optimum force flow. Despite the efficient use of material of well-designed shells, their construction suffers from labor-intensive and time-consuming fabrication techniques. This research therefore proposes a design method for the facilitated manufacturing of freeform shell structures. The manufacturing process has been considered from the design phase on, by generating an extensive range of different shell configurations based on a limited set of form-found modules and thus formworks. The challenge was to define which curved module geometries, after assembly, lead to the largest variety of freeform surfaces. More than sixty configurations resulted from a set of four modules only. This paper will discuss the form-finding process as well as the geometrical arrangement using tessellation patterns for the achievement of those modular configurations, going from domed to undulating shell shapes. In order to evaluate the structural efficiency of the shapes, twenty modular configurations were selected and analyzed under self-weight, using finite element simulations. To conclude, a prototype of one modular base element has been built, using a reusable casting wax in combination with a grid shell box, as the main parts of the formwork. The results demonstrate the structural feasibility and limitations of the modular shell design strategy. The modular approach contributes to circularity by encouraging reuse and allowing various combinations with a repeating set of modules, striving as such towards resource-effective innovative shell structures.

PEMANFAATAN LIMBAH ROTI MENJADI PRODUK YANG BERNILAI GUNA MENUJU PENERAPAN CIRCULAR ECONOMY

Bread is one of the products that are mostly produced by small and medium industries (SMEs). Along with the increase in bread production by SMEs, it has the potential to cause many environmental problems. The main environmental problems faced by the bread industry are waste management, efficient use of materials, water and energy during the production process. One solution that can be done to solve these problems is through the application of the circular economy concept. This research aims to study the production process of various flavours of bread and analyse the potential application of the circular economy concept for the development of a sustainable bakery industry by utilising bread waste into valuable products, and to learn how waste is handled in the bakery industry. The research was conducted through field observations and literature studies. The research data were processed, analysed and presented descriptively qualitatively. The results of the study show that the concept of circular economy that can be adopted in the bakery industry such as the utilisation of solid waste in the form of pieces of peeled white bread and unsold bread scraps, as animal feed ingredients.

Industrial automation and robotics in AAC industry: Selected models and case studies

AbstractAs the global manufacturing industry entered its fourth revolution (4IR, or Industry 4.0), innovations such as robotics, automation, and artificial intelligence are set to take over and improving the global industries. As the number of active industrial robots worldwide is increasing every day in different applications and industries automation continues to create new types of robots with improved utility and function. In the AAC Industry, these innovations already took place for some time in different process phases and applications such as oiling, autoclaves stacking pins, handling, packing, and so forth. Through this research, advantages commonly attributed to automation and robotics include higher production rates and increased productivity, more efficient use of materials, better product quality, improved safety, shorter workweeks for labor, and reduced factory lead times. Especially reduced scrap and waste through improved accuracy, increased efficiency, and operation around the clock could be emphasized. Based on the accumulated experience of WKB Systems GmbH in the field of the forging industry, selected models, real‐life application case studies, and implementation of different robotics in the AAC industry are discussed in this paper. These examples such as linear robots for autoclaves stacking pins, articulated robots for AAC packing and sorting line, and hybrid systems for handling and packing AAC insulation boards are studied in detail.

Melamine Acetate Preparation as a Urea-Formaldehyde Resin Additive for Particleboard Production

Urea-formaldehyde (UF) resin binders for wood-based panel production often use melamine as an additive to improve both mechanical properties and environmental compliance. Direct fortification for efficient use of melamine remains a problem due to low solubility. Pizzi & coworkers suggested the use of more soluble melamine salts and demonstrated success in terms of product performance. However, their preparation method showed low productivity and inefficient use of material and energy. In their scheme, a batch reactor fed with 1 kg of water and 75 g of a stoichiometric amount of melamine and acetic acid produced only around 25 g of solid melamine acetate crystal. In contrast, the remaining 50 g remained dissolved in 991 g of water, which requires high of energy to evaporate. This paper reports an attempt to increase batch productivity and work towards the more efficient use of material and energy. The experiment showed that the successive addition of melamine and acetic acid to the batch up to the solubility limit of melamine at the same reaction condition increased melamine and acetic acid fed from 75 g to 165 g. This was followed by a significant increase in dry crystal yield from 25 g to 117 - 132 g. Feeding the mother liquor to the next batch decreased the water use to only 8% of the original requirement. This resulted in a highly efficient process, eliminating the need for energy-intensive melamine acetate recovery from the mother liquor. The addition of 2% - 4% wt. of the product to UF resin resulted in particleboard with significantly lower thickness swelling, an increase in MOR & IB strength, and lower formaldehyde emission.

The Dynamics of Sustainable Material Selection for Green-Certified Projects

Material selection is a challenging process in which several parameters should be considered for green-certified projects. Hence, this study investigates the dynamics of sustainable material selection (SMS) across the project life cycle using system thinking. A dynamic model was developed based on the Leadership in Energy and Environmental Design where relevant environmental categories and credits were represented, and their dependency coefficients (DCs) were computed. This pinpointed the effect of SMS on the point-accrual pattern across project phases, showing that the high leverage points were demonstrated for the operation phase. The result showed that SMS extended beyond the efficient use of materials, which indicated a DC of 100% in the Materials and Resources category to affect other sustainable categories, i.e., the indoor environmental quality, energy efficiency, and sustainability of the project site comprised 68.8%, 57.6%, and 50% of DCs, respectively. Thus, optimal SMS could earn the project 48% of the total possible points, putting it in the ‘Certified’ level. Accordingly, the proposed model can be used to evaluate the level of certification as well as the building performance therein.

Multi-level performance-based seismic design optimisation of RC frames

Conventional structural optimisation techniques often result in unconventional structural configurations, unrealistic structural elements and ignore actual construction costs. This paper presents an effective performance-based optimisation framework for minimising initial material costs of realistic multi-storey reinforced concrete (RC) frames, while satisfying pre-determined performance targets under multiple seismic hazard levels as well as a set of practical design and construction constraints. A new low computational-cost optimisation method is proposed to directly control specific response parameters at both the element and structural levels (i.e. plastic rotation and inter-storey drift). For the first time, the concept of Uniform Damage Distribution (UDD) is adopted to simplify the complex design optimisation problem of RC buildings with multiple design variables in terms of section sizes and reinforcement ratios. The optimum design solution is achieved by gradually redistributing materials from strong to weak parts of the structure, aiming to fully exploit the material capacity. The efficiency of the proposed optimisation framework is then demonstrated in the optimum designs of 3-, 5-, 10- and 15-storey RC frames under a set of six spectrum-compatible earthquake records. The results indicate that compared to structures designed by current codes, optimum solutions required up to 20 % and 43 % less concrete volume and steel reinforcement weight, respectively. It is also noted that due to more efficient use of materials, optimum structures exhibited considerably lower global damage index (up to 88 %), less maximum inter-storey drift (up to 58 %), and less maximum plastic rotations (up to 78 %). Sensitivity analysis on earthquake record selection shows that using a single earthquake record may not lead to reliable design solutions, in particular for tall buildings, and hence a set of spectrum-compatible records should be used in the optimisation process. This research will lead to more economical and safe design of multi-storey RC structures in seismic regions by developing a practical multi-level optimisation method with low computational costs.