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Numerical analysis of the influence of the contact boundary condition and specimen geometry on concrete compressive strength

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Procedia Structural Integrity 2023年 47卷 261-267页

作者： Caroline Bremm Luísa Inda Leandro Ferreira Friedrich Sabrina Vantadori Ignacio Iturrioz Luis Kosteski Engineering Post Graduation Program Federal University of Pampa Av. Tiaraju 810 Alegrete 97546-550 Brazil Civil Engineering Graduate Program Federal University of Pampa Av. Tiaraju 810 Alegrete 97546-550 Brazil Program of Mechanical Pos-Graduation Federal University of Rio Grande do Sul Sarmento Leite 425 Porto Alegre 90040-060 Brazil Department of Engineering & Architecture University of Parma Parco Area delle Scienze 181/A 43124 Parma Italy

In the present paper, the influence of the contact boundary condition and specimen geometry on the concrete compressive strength is numerically investigated by using a version of the Lattice Discrete Element Method (LDEM), implemented on Abaqus/Explicit. More precisely, two types of contact boundary conditions are considered and, for each of them, three different slenderness levels (height/width ratio - h/b) are analyzed (that is, h/b = 0.5, 1.0, and 2.0) by considering a square cross-section. Moreover, for h/b = 2.0, a circular cross-section is also examined. Two models are developed: one by using the LDEM and the other by using a hybrid model, combining Finite Elements and LDEs. The results show that both the boundary conditions and the sample geometry influence the axial compressive strength.

关键词： Abaqus concrete compressive strength Lattice Discrete Element Method (LDEM)

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Effect of Method and Duration of Curing on the Compressive Strength of the Lime-Fly Ash Geopolymer Concrete 1

Effect of Method and Duration of Curing on the Compressive S...

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1st Progress in Science and Technology Research Symposium, PSTRS 2019

作者： Adam, Andi Arham Akifa, Sri Nur Siregar, Atur P.N. Mustofa Department of Civil Engineering Tadulako University Indonesia Post-Graduate Program Tadulako University Indonesia Department of Mechanical Engineering Tadulako University Indonesia

The use of lime to produce ambient cured Geopolymer concrete is one of a practical solution to avoid heat curing in the production of geopolymer concrete. The addition of lime in the geopolymer system will add another hardened mechanism, i.e. hydration in addition to condensation-polymerisation. This research aims to determine the influence of air and water curing on the strength of geopolymer concrete which uses class F fly ash and lime as raw materials. The geopolymer concrete was produced by varying the activator (sodium silicate and sodium hydroxide) with the variation of the activator to binder ratio of 0.45, 0.50, 0.55, and 0.60. Five per cent of the fly ash was replaced by slaked lime and the water added to the mix to maintain the ratio of water to solid (activator + binder) to 0.32. The test specimens were 100 mm dia x 200 mm height cylinder. Water-immersion curing was performed for 7, 14, and 21 days and the compressive strength test was done at 28 days. The results show that there is a difference in the curing process between the geopolymer concrete and the normal concrete. In the geopolymer concrete, there is a decrease in compressive strength if soaked for seven days and recovered with the increase in the age of immersion. Whereas for normal concrete, the compressive strength continues to increase with increasing age of immersion. © Published under licence by IOP Publishing Ltd.

关键词： Compressive strength

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Extremum Seeking Boundary Control for Euler-Bernoulli Beam PDEs

arXiv

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arXiv 2025年

作者： Biazetto, Paulo H.F. de Andrade, Gustavo A. Oliveira, Tiago Roux Krstic, Miroslav Post-graduate Program in Automation and Systems Engineering Federal University of Santa Catarina Florianópolis88040-370 Brazil Department of Automation and Systems Engineering Federal University of Santa Catarina Florianópolis88040-370 Brazil Department of Electronics and Telecommunication Engineering State University of Rio de Janeiro Rio de Janeiro20550-900 Brazil Department of Mechanical and Aerospace Engineering University of California San DiegoCA92093-0411 United States

This paper presents the design and analysis of an extremum seeking (ES) controller for scalar static maps in the context of infinite-dimensional dynamics governed by the 1D Euler-Bernoulli (EB) beam Partial Differential Equation (PDE). The beam is actuated at one end (using position and moment actuators). The map’s input is the displacement at the beam’s uncontrolled end, which is subject to a sliding boundary condition. Notably, ES for this class of PDEs remains unexplored in the existing literature. To compensate for PDE actuation dynamics, we employ a boundary control law via a backstepping transformation and averaging-based estimates for the gradient and Hessian of the static map to be optimized. This compensation controller leverages a Schrödinger equation representation of the EB beam and adapts existing backstepping designs to stabilize the beam. Using the semigroup and averaging theory in infinite dimensions, we prove local exponential convergence to a small neighborhood of the unknown optimal point. Finally, simulations illustrate the effectiveness of the design in optimizing the unknown static map. Copyright © 2025, The Authors. All rights reserved.

关键词： Schrodinger equation

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The impact of copper oxide nanoparticles reinforced nanocellulose acetate membrane on antibacterial and dye removal Potency

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Results in engineering 2024年 23卷

作者： Yanuhar, Uun Suryanto, Heru Amin, Muhamad Maulana, Jibril Mohamad Lal, Mohammad Tamrin Caesar, Nico Rahman Study Program of Aquatic Resources Management Faculty of Fisheries and Marine Sciences Universitas Brawijaya East Java Indonesia Department of Mechanical and Industrial Engineering Faculty of Engineering Universitas Negeri Malang Jl. Semarang 5 Malang65145 Indonesia Department of Aquaculture Faculty of Fisheries and Marine Universitas Airlangga Jl. Dharmahusada Permai Surabaya60115 Indonesia Borneo Marine Research Institute Universiti Malaysia Sabah Jalan UMS Sabah Kota Kinabalu88400 Malaysia Doctoral Program of Environment Science Post Graduate Program Universitas Brawijaya Jalan Veteran East Java Malang65145 Indonesia

With the rapid growth of the textile, leather, cosmetics, and pharmaceutical industries, concerns about pollutants in these sectors, especially dye pollutants, are increasing. This research characterizes bacterial nanocellulose acetate membranes made from Sargassum extract reinforced with copper oxide nanoparticles and tests their antibacterial properties and dye removal in water. Sargassum sp. extract was fermented using Acetobacter xylinum for 10 days, producing bacterial nanocellulose, which was then esterified to create bacterial nanocellulose acetate. Copper oxide nanoparticles were added to the bacterial nanocellulose acetate solution in varying concentrations, cast, and oven-dried. The membrane was analyzed using Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, antibacterial activity, and dye removal. Results showed uniform copper oxide nanoparticles distribution on the membrane surface. Structure analysis revealed diffraction peaks at 35.44° and 38.57°, indicating a reduced crystalline index but improved membrane effectiveness. Antibacterial tests showed a zone of inhibition against bacterial growth, increasing with higher copper oxide nanoparticle content. The addition of copper oxide nanoparticles also influenced the dye removal capacity for Metanil Yellow, Congo Red, Eosin Yellow, Methylene Blue, and Malachite Green. The kinetic analysis showed that the adsorption process follows a pseudo-first-order model, with higher correlation coefficients (R2) compared to the pseudo-second-order model. © 2024 The Author(s)

关键词： Fourier transform infrared spectroscopy

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A Delphi fuzzy analytic hierarchy process framework for criteria classification and prioritization in food supply chains under uncertainty

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Decision Analytics Journal 2023年 7卷

作者： Gupta, Srikant Chatterjee, Prasenjit Rastogi, Raghavendra Gonzalez, Ernesto D.R. Santibanez Department of Operations and Decision Sciences Jaipuria Institute of Management Jaipur India Department of Mechanical Engineering MCKV Institute of Engineering West Bengal 711204 India Post-Doctoral Fellow Management Graduate Program Universidade Paulista Indianópolis Campus Brazil Department of Applied Sciences Invertis University Uttar Pradesh Bareilly India Department of Industrial Engineering and CES 4.0 Faculty of Engineering University of Talca Curico Chile

Effectively managing food supply chains is critical for ensuring food security and safety. Identifying and prioritizing the criteria affecting food supply chain performance is imperative to manage uncertainty and avoid undesirable consequences in Supply Chain Management (SCM). This study aims to identify and prioritize critical criteria affecting food supply chains under uncertainty. We use the Delphi method to choose the predominating criteria classified into four groups: Resilience and Flexibility, Transparency and Traceability, Communication and Collaboration, and Regulation and Standardization. The fuzzy Analytic Hierarchy Process (FAHP) method is used next to prioritize the selected criteria based on their significance. The results show investment in research and development, transparency and traceability, risk-sharing and collaboration among stakeholders, are the top criteria for food supply chain security and safety. These findings contribute to formulating and developing effective strategies for securing food supply chains. © 2023 The Author(s)

关键词： Analytics hierarchy process Criteria classification and prioritization Delphi Food supply chain Fuzzy theory Multi-criteria decision-making

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Puncture behaviour simulation for varying striking velocity and indentation mass on BLARE laminated structures

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AIP Conference Proceedings 2024年第1期3022卷

作者： S. Arun Siva Kumar I. Siva Post Graduate Program in Manufacturing Engineering Kalasalingam Academy of Research and Education Anand Nagar Tamil Nadu India Professor Mechanical Engineering Mohan Babu University Tirupati 517102 Andhra Pradesh India

In recent years much research has been going on in Fiber Metal Laminate by the researcher and engineers because of its attractive properties. Along with that lot of Finite Element, Analysis-based studies are also employed to overcome the experimental test difficulty and fabrication of material. This research paper gives a detailed approach to Finite Element Analysis for high-velocity impact tests. The 3/2 stack up sequence of Aluminium 2024 and Basalt fabric is as follows, with the epoxy resin as the binding polymer. The varying parameter for this study is the impact velocity and mass of the indenter. From this study, energy, total displacement, and force are observed as a result. A uniform trend is observed in energy distribution between the various velocity.

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Multiscale investigation of seismic precursors before major earthquakes

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Mechanics Research Communications 2025年 147卷

作者： Friedrich, Leandro Ferreira Padilha, Mariana Hamdan Lacidogna, Giuseppe Iturrioz, Ignacio Graduate Program in Engineering Universidade Federal do Pampa Av. Tiaraju 810 CEP Alegrete97546-550 Brazil Department of Structural Geotechnical and Building Engineering Politecnico di Torino 24 Corso Duca degli Abruzzi Torino10129 Italy Mechanical Post-Graduate Program Universidade Federal do Rio Grande do Sul Sarmento Leite 425 CEP Porto Alegre90050-170 Brazil

In various mechanical systems, the study of damage processes can be approached from the perspective of continuous phase transition phenomena, a subject typically explored within the framework of statistical physics. This viewpoint enables a more refined interpretation of failure precursors, which are of great importance in the field. The present study investigates failure precursors through two case studies: the material failure process by using the Fiber Bundle Model and the seismicity of the 2023 Turkey Mw7.7 earthquake. To identify the criticality, two approaches are considered: (1) Natural Time (NT) analysis and (2) the Method of Critical Fluctuation-Based (MCF-B) approach. By comparing the evolution of precursors in both cases, the findings highlight their potential for predicting critical situations. © 2025 Elsevier Ltd

关键词： Large scale systems

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Quantification the morphological structure of bio-based membrane by high resolution of SEM imaging

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AIP Conference Proceedings 2023年第1期2477卷

作者： Afrillia Fahrina Sri Aprilia Muhammad Roil Bilad Nasrul Arahman Maughal Ahmed Ali Baig Avala Raji Reddy Department of Chemical Engineering Universitas Syiah Kuala Banda Aceh Indonesia Doctoral Program School of Engineering Post Graduate Program Universitas Syiah Kuala Banda Aceh Indonesia Faculty of Integrated Technologies Universiti Brunei Darussalam Brunei Darussalam Department of Mechanical Engineering CMR Technical Campus Hyderabad India

For the purpose of semi-permeable filtration system, membrane morphological structure determines the permeation quality. Membrane surface porosity, pore size distribution, symmetric and asymmetric structure in cross-section membrane play crucial role in transport properties. Therefore, scanning electron microscopy (SEM) plays important role to visualize the microscopical pore structure of membranes. In this study, bio-based composite membranes were prepared using non-solvent induced phase separation (NIPS) method. Polyvinylidene fluoride (PVDF) was employed as the main material, while ginger extract (GE) and SiO2 nanoparticles were used as additives. SEM image in this study provide information of membrane structure in surface and cross-section part. Furthermore, quantitative data of membranes in term of overall porosity is also presented. ImageJ tools is applied as software-aided SEM images processing method. The result analysis shows that addition of GE and SiO2 increase membrane porosity up to 70.81%.

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The strain and deflection analysis of wire mesh layer in hot asphalt mixtures using finite element method

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AIP Conference Proceedings 2023年第1期2711卷

作者： Romaynoor Ismy Sofyan M. Saleh Husaini M. Isya Doctoral Program School of Engineering Post Graduate Program Universitas Syiah Kuala Banda Aceh 23111 Indonesia Department of Civil Engineering Universitas Almuslim Matangglumpangdua 24261 Indonesia Department of Civil Engineering Universitas Syiah Kuala Banda Aceh 23111 Indonesia Department of Mechanical Engineering Universitas Syiah Kuala Banda Aceh 23111 Indonesia

Strain is closely related to the amount of load that can be held by an object so that it experiences deflection. A change in the size or shape of an object in holding a load causing stress is called strain. Strain and stress are forces that act on an object due to loads. The distribution analysis of the strain is needed to determine the phenomena that occur in an object due to loads to facilitate the analysis of wire mesh placement modeling. This research aimed to analyze the strain and deflection values that occur due to the loading of wire mesh layer on hot asphalt mixture. Analysis of strain and deflection values which are parameters of flexural resistance was carried out using ETABS software version 17.0.1. ETABS is one of the software used to solve structural problems related to the finite element method. Based on the research results, it was found that the modeling of wire mesh layering affects the flexural resistance value, strain, and deflection that occurred. The value of strain is inversely proportional to the value of the flexural resistance and is directly proportional to the deflection. The strain that occurs from the results of the study is between 0.0313 mm/mm to 0.038 mm/mm and The amount of deflection that occurs due to loading ranges from 8 to 9.5 mm. The best modeling is obtained on a hot asphalt mixture by laying wire mesh 30 mm from the surface of the test object with the lowest strain and able to withstand a maximum load of 291.85 KN.

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Evaluation of thermal and spectroscopic properties of hybrid biocomposite OPW/ramie fiber for materials building

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AIP Conference Proceedings 2023年第1期2554卷

作者： Indra Mawardi Samsul Rizal Sri Aprilia Muhammad Faisal 1Doctoral Program School of Engineering Post Graduate Program Universitas Syiah Kuala Banda Aceh 23111 Indonesia 2Department of Mechanical Engineering Politeknik Negeri Lhokseumawe Lhokseumawe 24301 Indonesia 3Department of Mechanical Engineering Universitas Syiah Kuala Banda Aceh 23111 Indonesia 4Department of Chemical Engineering Universitas Syiah Kuala Banda Aceh 23111 Indonesia

Environmentally friendly and sustainable buildings encourage researchers to develop natural fiber-based building materials. This investigation was prompted by the abundance of oil palm wood and the fact that it is rarely used as a building material. This study aims to investigate the thermal and spectroscopic properties of a hybrid bio-composite based on oil palm wood as a candidate for green building materials. The hybrid composite was fabricated from oil palm wood and ramie fiber as reinforcement and tapioca starch as a matrix. Oil palm wood particles and ramie fiber were pretreated in 100°C water and NaOH solution, respectively. Hybrid biocomposite was fabricated using hotpress at constant temperature and pressure, with variations of HBC1, HBC2, HBC3 and HBC4. Evaluation of thermal properties in thermogravimetric analysis, differential scanning calorimetry, and spectroscopic was carried out. Thermogravimetric and spectroscopic analysis showed that the HBC3 sample was more stable up to the temperature 358°C and the bigger crystal size is 3.45 nm, compared to other samples. These results showed that oil palm wood-based hybrid composites have the potential to be used as green building materials.

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