Hasil untuk "Mechanical industries"

J. Hartnett, T. Irvine, Young I Cho et al.

F. Krebs, M. Jørgensen, K. Norrman et al.

G. Çam, S. Mıstıkoğlu

Munonyedi Egbo

Abstract Composites or composite materials are engineered materials that consist of two or more constituent materials with wide discrepancies in their physical, chemical, and mechanical properties. The characteristic properties of these composite are as a result of the individual properties of their constituent parts and their respective volume fractions and arrangements in the material system. Depending on the intended application, composites can be designed to satisfy specific geometrical, structural, mechanical, chemical, and sometimes aesthetic requirements. Areas of application of these synthetic materials includes construction such as in buildings and bridges, automotive industry such as in car bodies, aeronautic, naval (e.g., ships and boats), and in the biomedical fields. Although metallic, polymeric and ceramic biomaterials have been in use for medical treatments such as tissue repairs and replacements for decades, composites are just coming to light. Therefore, the main purpose of this paper is to introduce composite materials and discuss their current and potential use in the biomedical field.

Rui Xiao, Pawel Polaczyk, Miaomiao Zhang et al.

As the concept of sustainable pavement gains prominence, a growing number of industrial wastes and recycled materials have been utilized in the pavement industry to preserve natural resources. This study investigates the potential use of waste glass powder-based geopolymer cement as a stabilizing agent in recycled waste glass aggregate (GA) bases. Two recycled materials, waste glass powder (GP) and class F fly ash (FF), were used as the raw materials in the preparation of geopolymer. Virgin aggregate (VA) was replaced by GA at varying replacement ratios as the pavement base materials, and the mechanical behaviors before and after geopolymer stabilization were evaluated. Without stabilization, the incorporation of over 10% GA caused significant detrimental effects on the California bearing ratios (CBR) of base materials, which should be carefully managed in pavement construction. However, all geopolymer stabilized samples showed decent strength properties, indicating the effectiveness of geopolymer stabilization. The use of GA reduced the drying shrinkage of base samples, although the mechanical properties were compromised. During the sample preparation, a higher curing temperature and relative humidity resulted in better mechanical behaviors, and the surface of GA could dissolve in alkaline solution and involve in the geopolymerization at 40°C. The microstructure and minerology of geopolymer stabilizer of base materials were characterized by scanning electron microscopy (SEM) and X-ray defraction (XRD) analyses. This study confirmed the promise of using waste glass-based pavement base materials as the greener substitutes and the potential synergy between waste glass recycling and the pavement industry.

David Olusola Fakorede, Friday Odohi Ebit, Adeniyi Emmanuel Daodu et al.

The optimal combination of Glass (G) and Carbon fibres (C) in epoxy composites remains challenging due to the complexities in determining the maximum mechanical, thermal, and microstructural properties. This study investigates the effects of hybrid reinforcement to enhance performance for advanced engineering applications. Hand lay-up lamination method was employed in which the reinforcement was constant at 40 wt% for all the composition. The study examined three key processing factors: (i) Reinforcement (R) with six variations of 0 wt%, 40 wt% G, 40 wt% C, 10G/30 wt% C, 10C/30 wt% G 20G/20 wt% C; (ii) Nature of Fibre (NF) in woven, unidirectional, and chopped forms; and (iii) Temperature (T) at 30 °C, 50 °C, and 70 °C. Using the Taguchi optimization method, L18 experimental samples were prepared, with tensile strength selected as the response parameter. Validation tests including microstructural, thermal and mechanical tests were conducted on the best four samples from the optimization The experimental results identified sample R5NF2T70 as having the highest tensile strength (160 MPa). This was corroborated by the Taguchi optimization, which also predicted R5NF2T70 (10C/30G woven fibre cured at 70 °C) as the optimal combination. Reinforcement emerged as the most significant processing facto, followed by Nature of Fibre and Temperature. Further validation of the top four optimized samples (R5NF1T50, R6NF1T70, R6NF2T30, and R5NF2T70) revealed that while R5NF2T70 exhibited superior tensile strength, thermal stability, hardness and flexural strength among the selected samples. Microstructural analysis of R5NF2T70 indicated a well-integrated composite structure. The consistent identification of R5NF2T70 as the best overall performing composite, considering its balance of properties, suggests its suitability for high-strength applications in various industries.

Murat Colak, Enes Aydin Muhammed, Mustafa Turkmen et al.

Aluminum and its alloys are widely used in many fields, such as automotive, aerospace, and defense industries, due to their many advantages. Due to such critical applications, the quality demands are also increasing. With the recent development in technologies, studies on casting of aluminum with different alloying element additions are ongoing rapidly. Various elements are added to the alloy to provide the desired properties. In this study, the effects of 0.03, 0.06, and 0.1 wt% Er addition to A356 aluminum alloy were evaluated simply because in the literature, only 0.1 wt% and above additions were studied. Samples were prepared using permanent molds and subjected to mechanical testing and microstructural characterization. Changes in the microstructure (evaluated via SDAS and SDAL) and mechanical properties of the cast specimens were analyzed. The results showed that Er addition improved tensile strength by up to 30%, increased elongation fourfold, and enhanced toughness by a factor of 4.5.

Xiaoxiao Cao, Meimei Feng, Haoran Bai et al.

Against the backdrop of increasingly severe global climate challenges, various industries are in urgent need of developing materials that can both improve performance and reduce carbon emissions. In this study, carbon dioxide nanobubble water (CO₂NBW) was evaluated as an innovative additive for cemented backfill materials (CBMs), and its optimization effect on the mechanical properties and microstructure of the materials was explored. The effects of different concentrations of CO₂NBW on stress–strain behavior, compressive strength, and microstructure were studied by uniaxial compression tests and scanning electron microscopy (SEM) analysis. The results show that with changes in CO₂NBW concentration and fractal dimension, the uniaxial compressive strength (UCS), peak strain, and elastic modulus of the specimens first increase and then decrease. At the optimal concentration level (<i>C</i> = 3) and fractal dimension (2.4150–2.6084), UCS reaches a peak value of 24.88 MPa, which is significantly higher than the initial value (<i>C</i> = 1). The peak strain and elastic modulus also reach maximum values of 0.01231 and 3.005 GPa, respectively. When the fractal dimension was between 2.4150 and 2.6084, the microstructural optimization effect of CO₂NBW on CBM was most significant, which was reflected in the compactness of the internal pore structure and the thoroughness of the hydration degree. In addition, based on the close correlation between peak strain and elastic modulus and UCS, a damage constitutive model of CBM specimens considering the influence of CO₂NBW concentration and fractal dimension was constructed. The study also found that the damage of CBM specimens is normally distributed with strain, and the accumulated damage in the plastic deformation stage dominates the total damage.

Fleur Hendriks, Vlado Menkovski, Martin Doškář et al.

Mechanical metamaterials often exhibit pattern transformations through instabilities, enabling applications in, e.g., soft robotics, sound reduction, and biomedicine. These transformations and their resulting mechanical properties are closely tied to the symmetries in these metamaterials' microstructures, which remain under-explored. Designing such materials is challenging due to the unbounded design space, and while machine learning offers promising tools, they require extensive training data. Here, we present a large dataset of 2D microstructures and their macroscopic mechanical responses in the hyperelastic, finite-strain regime, including buckling. The microstructures are generated using a novel method, which covers all 17 wallpaper symmetry groups and employs Bézier curves for a rich parametric space. Mechanical responses are obtained through finite element-based computational homogenization. The dataset includes 1,020 distinct geometries, each subjected to 12 loading trajectories, totaling 12,240 trajectories. Our dataset supports the development and benchmarking of surrogate models, facilitates the study of symmetry-property relationships, and enables investigations into symmetry-breaking during pattern transformations, potentially revealing emergent behavior in mechanical metamaterials.

Giovanni Bordiga, Jean-Gabriel Argaud, Audrey A. Watkins et al.

The concept of cloaking -- hiding objects from external detection -- has seen wide success in linear systems. Yet, translating these advancements to nonlinear mechanical systems remains an open challenge. Here, we present a new approach to nonlinear mechanical cloaking that frames cloaking as an optimization problem aimed at replicating a target mechanical response. We solve this problem using a differentiable simulation framework coupled with gradient-based optimization. We implement this approach in a class of mechanical metamaterials constructed from rigid units with elastic couplings that support large deformation and contact interactions. Using both numerical simulations and physical experiments, we design optimal cloak structures that effectively mask internal inhomogeneities and shield against external mechanical disturbances both in static and dynamic regimes. This approach provides a versatile design paradigm for creating mechanical systems with integrated cloaking functionality across a broad range of loading scenarios.

Abhishek Patange, Sharat Chidambaran, Prabhat Shankar et al.

Slug formation in oil and gas pipelines poses significant challenges to operational safety and efficiency, yet existing detection approaches are often offline, require domain expertise, and lack real-time interpretability. We present an interactive application that enables end-to-end data-driven slug detection through a compact and user-friendly interface. The system integrates data exploration and labeling, configurable model training and evaluation with multiple classifiers, visualization of classification results with time-series overlays, and a real-time inference module that generates persistence-based alerts when slug events are detected. The demo supports seamless workflows from labeled CSV uploads to live inference on unseen datasets, making it lightweight, portable, and easily deployable. By combining domain-relevant analytics with novel UI/UX features such as snapshot persistence, visual labeling, and real-time alerting, our tool adds significant dissemination value as both a research prototype and a practical industrial application. The demo showcases how interactive human-in-the-loop ML systems can bridge the gap between data science methods and real-world decision-making in critical process industries, with broader applicability to time-series fault diagnosis tasks beyond oil and gas.

Aman Verma, Keshav Samdani, Mohd. Samiuddin Shafi

This paper presents the design, implementation, and evolution of a comprehensive multimodal room-monitoring system that integrates synchronized video and audio processing for real-time activity recognition and anomaly detection. We describe two iterations of the system: an initial lightweight implementation using YOLOv8, ByteTrack, and the Audio Spectrogram Transformer (AST), and an advanced version that incorporates multi-model audio ensembles, hybrid object detection, bidirectional cross-modal attention, and multi-method anomaly detection. The evolution demonstrates significant improvements in accuracy, robustness, and industrial applicability. The advanced system combines three audio models (AST, Wav2Vec2, and HuBERT) for comprehensive audio understanding, dual object detectors (YOLO and DETR) for improved accuracy, and sophisticated fusion mechanisms for enhanced cross-modal learning. Experimental evaluation shows the system's effectiveness in general monitoring scenarios as well as specialized industrial safety applications, achieving real-time performance on standard hardware while maintaining high accuracy.

Walter Alabiso, S. Schlögl

Thermosets are known to be very reliable polymeric materials for high-performance and light-weight applications, due to their retained dimensional stability, chemical inertia and rigidity over a broad range of temperatures. However, once fully cured, they cannot be easily reshaped or reprocessed, thus leaving still unsolved the issues of recycling and the lack of technological flexibility. Vitrimers, introduced by Leibler et al. in 2011, are a valiant step in the direction of bridging the chasm between thermoplastics and thermosets. Owing to their dynamic covalent networks, they can retain mechanical stability and solvent resistance, but can also flow on demand upon heating. More generally, the family of Covalent Adaptable Networks (CANs) is gleaming with astounding potential, thanks to the huge variety of chemistries that may enable bond exchange. Arising from this signature feature, intriguing properties such as self-healing, recyclability and weldability may expand the horizons for thermosets in terms of improved life-span, sustainability and overall enhanced functionality and versatility. In this review, we present a comprehensive overview of the most promising studies featuring CANs and vitrimers specifically, with particular regard for their industrial applications. Investigations into composites and sustainable vitrimers from epoxy-based and elastomeric networks are covered in detail.

Amer Hassan, M. Arif, M. Shariq

Abstract The traditional concrete is one of the most energy-intensive construction materials responsible for about 10% of global anthropogenic carbon dioxide emissions. Efforts are being made to develop an alternative binder for concrete. The geopolymer concrete (GPC) has emerged as a promising novel construction material for the production of cement and provides a clean technology option for sustainable development. This paper undertakes a review of the performance behaviour of reinforced geopolymer concrete structural elements and summarises the findings on the mechanical performance of reinforced GPC elements, e.g., columns, beams, and walls. In this review study, the mechanical properties of GPC structural elements have been investigated and compared with that of OPC concrete. The failure mode of GPC structural element has also been reported, and it was almost in the same manner of OPC concrete failure. The potential of GPC with regards to the chemical resistance and heat resistance could be significantly employed in the various industrial constructions such as marine constructions, pavements, and sewage pipes, etc. Moreover, it was observed that GPC could be safely used in structural elements owing to its excellent mechanical properties using provisions of design codes. More experimental studies are required to give a better understanding of the mechanical properties of GPC for its mass utilization in diversified application areas and spread the clean technology option in the construction industry.

Chang Sun, Lulu Chen, Jianzhuang Xiao et al.

Abstract This paper investigates the utilization of powder recycled from construction and industrial waste in the construction industry. To alleviate the negative environmental impact of cement industry, recycled concrete powder (RCP) and spontaneous combustion gangue powder (SCGP) were used as supplementary materials to substitute part of the cement. Six recycled mortar mixes were designed with various contents of RCP and SCGP. In this test, the total replacement ratio of the recycled powder (RCP and SCGP) varied from 0 to 50%. The mechanical and durability properties of the recycled mortar were investigated in combination with microstructure analysis. The findings reveal that 15% RCP and 15% SCGP is a suitable combination for the recycled mortar to maintain mechanical properties comparable to those of the control mix. When the total substitution ratio of RCP and SCGP does not exceed 30%, their incorporation leads to better durability properties of the recycled mortar compared to those of the mix containing one type of recycled powder. Consistent with the mechanical and durability analyses, the microstructure analysis reveals that the combination of 15% RCP and 15% SCGP contributes to a dense structure of the mortar, which benefits from the synergetic effect of the relatively high pozzolanic reactivity of SCGP and the filling ability of RCP.

M. Michelin, Daniel G. Gomes, A. Romaní et al.

Increasing environmental and sustainability concerns, caused by current population growth, has promoted a raising utilization of renewable bio-resources for the production of materials and energy. Recently, nanocellulose (NC) has been receiving great attention due to its many attractive features such as non-toxic nature, biocompatibility, and biodegradability, associated with its mechanical properties and those related to its nanoscale, emerging as a promising material in many sectors, namely packaging, regenerative medicine, and electronics, among others. Nanofibers and nanocrystals, derived from cellulose sources, have been mainly produced by mechanical and chemical treatments; however, the use of cellulases to obtain NC attracted much attention due to their environmentally friendly character. This review presents an overview of general concepts in NC production. Especial emphasis is given to enzymatic hydrolysis processes using cellulases and the utilization of pulp and paper industry residues. Integrated process for the production of NC and other high-value products through enzymatic hydrolysis is also approached. Major challenges found in this context are discussed along with its properties, potential application, and future perspectives of the use of enzymatic hydrolysis as a pretreatment in the scale-up of NC production.

V. Souza, J. Pires, C. Rodrigues et al.

Chitosan-based composites play an important role in food packaging applications and can be used either as films or as edible coatings. Due to their high costs and lower performance (i.e., lower barrier against water vapor, thermal, and mechanical properties) when compared to the traditional petroleum-based plastics, the use of such biopolymers in large-scale is still limited. Several approaches of chitosan composites in the packaging industry are emerging to overcome some of the disadvantages of pristine polymers. Thus, this work intends to present the current trends and the future challenges towards production and application of chitosan composites in the food packaging industry.

A. Shyam, Shibayan Roy, Dongwon Shin et al.

Abstract Commonly used commercial cast aluminum alloys for the automotive industry are viable for temperatures only up to 250 °C, despite decades of study and development. Affordable cast aluminum alloys with improved high-temperature mechanical properties are needed to enable the next generation of higher efficiency passenger car engines. Metastable θ′ (Al2Cu) precipitates contribute to strengthening in Al–Cu alloys, but above 250 °C coarsen and transform, leading to poor mechanical properties. A major challenge has been to inhibit coarsening and transformation by stabilizing the metastable precipitates to higher temperatures. Here, we report compositions and associated counter-intuitive microstructures that allow cast Al–Cu alloys to retain their strength after lengthy exposures up to 350 °C, ∼70% of their absolute melting point. Atomic-scale characterization along with first-principles calculations demonstrate that microalloying with Mn and Zr (while simultaneously limiting Si to

K. Liew, Z. Pan, Lu-Wen Zhang

M. Janczarek, Ł. Klapiszewski, Patryk Jędrzejczak et al.

Abstract The intensive development of construction in recent years and the increasing demands on the durability and service life of buildings have increasingly made the construction industry pay attention to new materials solutions based on nanotechnology. One of such solutions is the use of titanium dioxide with photocatalytic and antibacterial properties in building materials. Although this solution has been known for decades, there are few articles that review the latest trends in this area. Compared to other literature studies, this article pays particular attention to the possibility of modifying nanotitania to expand its photocatalytic properties and analyses the effects of these alterations on the self-cleaning, smog-abating and antibacterial properties of building materials, mainly cement-based composites. It is complemented by a section dedicated to the mechanical and durability properties of pristine and functionalized TiO2-modified building materials, taking into account dispersion methods, rheological and mechanical parameters as well as resistance to external factors.