Structural Integrity Research Articles

Corrosion-induced thickness diminution of an ageing bulk carrier

The 2030 Agenda for Sustainable Development introduced 17 Sustainable Development Goals (SDGs). The International Maritime Organization (IMO) has endorsed connections between the maritime sector and SDGs, emphasising sustainable production in the marine environment. Consequently, technical considerations, such as ship structure sustainability, are crucial for marine safety. The impact of corrosion influences the structural degradation of vessels and the risk of structural failure and fuel oil spills significantly. The formulation of predictive corrosion models, grounded in historical data accumulated during vessel operations, emerges as an optimal strategy for designing structural elements and guaranteeing their structural integrity. This paper analyses non-linear deterministic and stochastic corrosion models, focusing on an ageing bulk carrier, to provide design-phase information for sustainable structures. Utilising data on measured steel plate thickness over a 20-year operational period, non-linear models are employed to calculate the millimetres of thickness diminution. Assuming corrosion onset at 7, 8, and 9 years, corresponding coefficients are computed, based on the developed model. A model is also considered, in which there were no assumptions about the beginning of corrosion initiation. The corresponding annual corrosion rate was observed separately in each of the models, as a deterministic variable and as a probabilistic random variable. This approach aims to enhance the understanding of the causal relationship between corrosion processes and structural performance, contributing to the development of sustainable design practices in the maritime industry.

Evaluation of canalis sinuosus and accessory canal morphology by cone-beam computed tomography.

To evaluate canalis sinuosus (CS) and accessory canalis sinuosus (AC) morphology and their relationship with the impacted canine on cone-beam computed tomography (CBCT) images. The diameter and location of the CS, its distance from the nasal cavity (NC-CS), its distance from the buccal cortical plate (BC-CS), and its distance from the alveolar ridge crest (AR-CS) were evaluated on 1000 CBCT scans. The prevalence and termination of AC and the presence of impacted canines were also evaluated. CS was detected in 89 (8.9%) of 1000 CBCTs. The mean CS diameter was found as 1.34 ± 0.53mm. No statistically significant difference was found between gender, age, direction, and CS presence and diameter. CS was most frequently seen in regions 11 (23.6%) and 13 (23.6%). The average NC-CS, BC-CS, and AR-CS length was 6.14, 6.06 and 4.35mm, respectively. AC was detected in 22 patients (24.71%). There was no statistically significant difference between the presence of AC and gender, age, CS diameter, NC-CS, BC-CS, and AR-CS distance. BC-CS length and AR-CS length were statistically significantly higher in patients with impacted canines. It should be kept in mind that the CS diameter, NC-CS, BC-CS, and AR-CS distance may increase in the presence of an impacted canine and the integrity of the neurovascular structure should be preserved. The fact that the CS is often localized in the palatial region requires a detailed evaluation of the anterior maxillary region with three-dimensional imaging methods.

Structural And Functional Integrity Of The Visual System Following A Collision-sport Season

Structural And Functional Integrity Of The Visual System Following A Collision-sport Season

Enhancing uterine receptivity for embryo implantation through controlled collagenase intervention.

Ineffective endometrial matrix remodeling, a key factor in infertility, impedes embryo implantation in the uterine wall. Our study reveals the cellular and molecular impact of human collagenase-1 administration in mouse uteri, demonstrating enhanced embryo implantation rates. Collagenase-1 promotes remodeling of the endometrial ECM, degrading collagen fibers and proteoglycans. This process releases matrix-bound bioactive factors (e.g., VEGF, decorin), facilitating vascular permeability and angiogenesis. Collagenase-1 elevates embryo implantation regulators, including NK cell infiltration and the key cytokine LIF. Remarkably, uterine tissue maintains structural integrity despite reduced endometrial collagen fiber tension. In-utero collagenase-1 application rescues implantation in heat stress and embryo transfer models, known for low implantation rates. Importantly, ex vivo exposure of human uterine tissue to collagenase-1 induces collagen de-tensioning and VEGF release, mirroring remodeling observed in mice. Our research highlights the potential of collagenases to induce and orchestrate cellular and molecular processes enhancing uterine receptivity for effective embryo implantation. This innovative approach underscores ECM remodeling mechanisms critical for embryo implantation.

Si-P-Cu internally bonded anode: An innovative strategy for low-cost and high-performance pseudocapacitive Li-ion storage

Maintaining the structural integrity of silicon and phosphorus anodes during the Li+ insertion and extraction cycles poses a significant challenge. Inspired by the natural process of plant roots anchoring into soil, we present a simple yet effective method for integrating a SiP anode into the copper current collector. This approach involves subjecting readily available and cost-effective micrometre-sized silicon particles (50–150 μm) and red phosphorus to mechanochemical treatment. Subsequently, the resulting Si/P composite is coated onto copper foil and subjected to annealing treatment, resulting in the formation of an integrated structure, incorporating Cu3Si, Cu3P, and P-doped Si, firmly established within the copper current collector. The electrode obtained (BM-Si@P/Cu-350), promoted by a crosslinked (polyimide) PI binder, outperforms not only the ball-milled Si and red P but also the same electrode in which the annealing process is absent (BM-Si@P/Cu-100). During the mechanochemical treatment, red P acts as both the doping agent and a lubricant, facilitating the grinding of the Si particles into P-doped Si particles in the range of predominantly 200–300 nm; while during the thermal treatment, Si plays a key role in preventing excessive interaction between the P and the Cu current collector. Instead, a tailored rooting of the active material into the current collector is achieved through the formation of Cu3P and Cu3Si phases, not only increasing the mechanical stability of the electrode to endure volume changes during cycling and limit developing cracks, but also enhancing the electrical conductivity of the system. This article suggests a simple and potentially low-cost strategy for the utilization of highly available micrometre-sized silicon and red-P for Li-ion storage applications.

Analysis and Design of Electrical Transmission Towers with Various Sections and Bracing Configurations

Abstract: This study focuses on the analysis and design of a 400kV electrical transmission tower with a height of 50 meters. The tower was modeled in STAAD.PRO using three distinct steel sections Angle, Tube, and Channel combined with various bracing configurations, including X, K, and D-bracings. The main objective of this study is to determine the most efficient and economical configuration for the design of Transmission tower. The tower is analyzed for Dead load, Live load and wind load as per the codes. The study concludes that transmission towers with angled sections and X-bracing exhibit moderate displacement, minimal reaction forces, and reduced structural weight, making them a preferred design choice. Manual calculations were performed to design the connections and footing, ensuring structural integrity. The results confirm that the tower's connection design is safe and reliable

Analysis of Reinforced Concrete Structure Subjected to Blast Load

The research focuses on a specific standoff distance of 15m & 20m , a critical parameter in blast analysis, to gain a understanding of the building's behavior under static loading conditions of blast load weight of 150kgs & 100kgs of TNT. To simulate realistic scenarios, the models are subjected to appropriate boundary conditions, including foundation constraints to account for the building's interaction with the ground. The blast load is assigned as joint loads, considering the standoff distance of the blast from the source. The standoff distance significantly influences the building's response to the blast, with profound implications for structural integrity and security. The Analysis of the Bare frame with blast load added as Joint Load, the deflection is controlled by adding Shear walls along various location along the periphery & core for 10 Story RCC Structures. The analysis is conducted using linear time history analysis (Response Spectrum Analysis) within ETABS, capturing the response of the building. Roof Displacement, Base Shear, Story Drift, Stiffness, Time period & Modal participation mass ratios are monitored during the analysis. The outcomes of this study contribute valuable insights into the structural responses of buildings to blast loads at specific standoff distances. This research advances our understanding of blast effects on buildings thereby enhancing the security and resilience of vital infrastructure in the face of evolving threats. Keywords: Blast Load, Response Spectrum Method, Roof Displacement, Base Shear, Story Drift, Stiffness, Time period & Modal participation mass ratios.

A comprehensive review on crack detection schemes and modelling techniques in high-speed rotor systems

ABSTRACT The combination of a rotor and bearings plays a pivotal role in various industrial applications, including gas turbines, compressors, turbochargers, aircraft engines, and wind generators. Ensuring the structural integrity of the rotor-bearing assembly during static and dynamic conditions is most important, as any failure could lead to unpredictable losses. Due to their continuous operation, high-speed rotors are more susceptible to faults such as misalignment, bow, eccentricity, and cracks. Among these faults, cracks are the most predominant fault that affects the system’s reliability. Despite significant advancements in rotor dynamics, cracks still threaten the integrity and performance of the rotor-bearing assembly. This review paper aims to thoroughly review the challenges and issues associated with crack formation in high-speed rotor systems. Various crack detection methods are also explored using vibration signals obtained from the rotor-bearing unit and their associated processing techniques. This study also gives an extensive overview of different crack modelling and analysis techniques. Furthermore, a novel rotor-bearing model is modelled using the finite element method, and the numerical results obtained from this model are validated with the existing literature model. This review paper will serve as a valuable resource for researchers that offers insights into the latest advancements and emphasises the importance of crack detection for ensuring the reliability of high-speed rotor systems.

Shear behavior of RC beams with openings under impact loads: unveiling the effects of HSC and RECC

Incorporating transverse openings in reinforced concrete (RC) beams reduces their load-bearing capacity and stiffness, making them prone to premature failure. This highlights the need for a more nuanced understanding of their behavior to ensure structural integrity, particularly under impact loads. This research delves into a relatively unexplored area, investigating the impact performance of RC beams containing openings through numerical analysis. By comparing different concrete types, the study seeks to identify optimal materials for such applications. The concrete damage plasticity model, accounting for strain rate effects, will be employed to simulate the material behavior of normal-strength concrete (NSC), high-strength concrete (HSC), and a novel eco-friendly alternative: rubberized engineered cementitious composite (RECC). RECC incorporates recycled tire rubber as a partial substitute for traditional concrete aggregates, offering a sustainable solution while mitigating environmental hazards associated with waste tire incineration. The finite element models are validated with experimental results, accurately predicting ultimate capacities, failure modes, and post-cracking response in RC beams (with/without openings) under static/impact loads. A comprehensive parametric analysis investigates the effects of concrete strength, impact energy, impactor mass, drop height, and opening location, providing valuable insights into how these factors influence the impact behavior under drop-weight testing. The results reveal that openings in RC beams under impact loads significantly reduce strength and stiffness, with detrimental effects observed for dual shear-zone openings. Surprisingly, a small mid-span opening can enhance impact response. HSC beams exhibit lower initial displacements but higher residual values, while RECC improves overall behavior in beams with openings, reducing maximum displacement and promoting energy dissipation for improved post-impact recovery.

Edifices Created with Precast and Prefabricated Components

Typically, the precast and prestressed concrete courses encompass various topics vital for understanding and applying the principles of prestressed concrete design and construction. This paper is designed to educate students on precast and prestressed concrete's theory and practical aspects, emphasizing the importance of understanding the mechanics, design principles, and construction techniques involved. By the end of this paper, one will have a solid foundation in working with these materials and be prepared to apply their knowledge in real-world scenarios. Comprehending the basic principles of prestressing, encompassing a range of systems and techniques employed within the field, is crucial for professionals in the industry. By delving into the core concepts of prestressing, individuals can gain a deeper insight into how this method enhances the structural integrity of various construction projects. Understanding the different systems and strategies utilized in prestressing allows engineers and architects to make informed decisions when designing and implementing their projects.

Comparison of Bending Stiffness between String of Pearls Plate-Bone Substitute Constructs with and without Bending Tees in a Fracture Gap Model

Abstract Objective The aim of this study was to compare the bending properties of String of Pearls plate-bone substitute constructs with and without bending tees in the nodes over a simulated fracture gap. It is hypothesized that the constructs with tees will have higher bending stiffness. Study Design Acetal polymer tubes and 12-hole, 3.5-mm String of Pearls plates were used to create plate-bone substitute constructs simulating stabilization in a bridging fashion over a 45-mm gap. Twenty-four constructs were made with 12 containing tees in the nodes over the fracture gap. Single-cycle load-to-failure 4-point bending was performed in mediolateral and craniocaudal planes. Bending stiffness was compared with a t-test (p < 0.05). Results All plate-bone substitute constructs had a permanent loss of structural integrity via plastic deformation of the plate. The bending stiffness (mean ± standard deviation) of the craniocaudal group was 59.11 ± 1.98 N/mm with tees and 59.25 ± 1.69 N/mm without tees (p = 0.88). In the mediolateral group, the bending stiffness was 43.17 ± 0.75 N/mm with tees and 41.09 ± 0.91 N/mm without tees (p = 0.0042). Conclusion In 4-point bending, the plate-bone substitute constructs with tees had equivalent bending stiffness in the craniocaudal plane and increased bending stiffness in the mediolateral plane. However, with a small absolute difference in values, the clinical significance is unclear. Future studies for cyclic bending, torsional, and axial compression tests should be performed to further investigate the value of tees in the nodes over a comminuted or gap fracture repaired in a bridging fashion.

Specifics of Experimental and Fem Approaches in Structural Integrity Assesment of Penstock Made of HSLA Steel

Taking into account the history of problems concerning high-strength low-alloyed (HSLA) steel used for manufacturing of penstocks (partly presented by authors in previous studies), this paper is oriented toward specifics on structural integrity assessment of construction in question. Experimental testing of parent material, i.e. HSLA steel, such as microstructure analysis, impact toughness testing and hardness measuring provide insight into characteristics of parent material properties. Considering geometry of penstock and specific requirements, finite element method (FEM), i.e. ABAQUS, was used to assess the structural integrity of penstock as a whole, specific the longitudinal welded joint under the different internal (working) pressure. It should be emphasized that a slight undermatching effect was investigated by FEM approach in this case. Focus is being put on plastic deformation investigation on aforementioned welded joint under maximum internal pressure of 120 bar.

Experimental study on residual compressive bearing capacity of cracked reinforced concrete columns by SCDA

Abstract The static demolition of structures via using soundless chemical demolition agent (SCDA) is attracting increasing attention because of its environmental friendliness and safety, especially in the dense urban areas. However, the research on the application of SCDA in demolishing the reinforced concrete is still scarce, seriously limiting the development of static demolition. In this work, with the combined efforts of experiments and theoretical analysis, we investigate the critical role of borehole layouts in the static demolition of reinforced concrete (RC) by determining the occurrence and expansion of cracks during static demolition, and the resulting residual mechanical properties of RC. We show that the growth of cracks is significantly dependent on the reaction of SCDA, while the crack development mode is mainly controlled by the layouts of boreholes. We demonstrate that cracks formed in static demolition process can significantly reduce the strength of RC and change its failure mode. We further point out the key factor controlling the failure of RC under axial compression (i.e., the integrity of structures), and the RC with larger crack size and less structural integrity is more prone to fail. The results and findings in this work further clarify the role of borehole layouts and are of great significance in improving the efficiency of static demolition.

A Comparative Study of Machine Learning and Conventional Techniques in Predicting Compressive Strength of Concrete with Eggshell and Glass Powder Additives

Recent research has focused on assessing the effectiveness of response surface methodology (RSM), a non-machine learning technique, and artificial neural networks (ANN), a machine learning approach, for predicting concrete performance. This research aims to predict and simulate the compressive strength of concrete that replaces cement and fine aggregate with waste materials such as eggshell powder (ESP) and waste glass powder (WGP) for sustainable construction materials. In order to ensure concrete’s durability and structural integrity, a compressive strength evaluation is essential. Precise predictions maximize efficiency and advance sustainability, particularly when dealing with waste materials like ESP and WGP. The response surface methodology (RSM) and artificial neural network (ANN) techniques are used to accomplish this for practical applications in the built environment. A dataset comprising previously published research was used to assess ANN and RSM’s predictive and generalization abilities. To model and improve the model, ANN used seven independent variables, while three variables, cement, waste glass powder, and eggshell powder, improved the RSM. Both the ANN and RSM techniques are effective instruments for predicting compressive strength, according to the statistical results, which include mean squared error (MSE), determination coefficient (R2), and adjusted coefficient (R2 adj). RSM was able to achieve the R2 by 0.8729 and 0.7532 for compressive strength, while the accuracy of the results for ANN was 0.907 and 0.956 for compressive strength. Moreover, the correlation between ANN and RSM models and experimental data is high. The artificial neural network model, however, exhibits superior accuracy.

Enhancing Power and Thermal Gradient of Solar Photovoltaic Panels with Torched Fly-Ash Tiles for Greener Buildings

Solar photovoltaic (PV) panels that use polycrystalline silicon cells are a promising technique for producing renewable energy, although research on the cells’ efficiency and thermal control is still ongoing. This experimental research aims to investigate a novel way to improve power output and thermal performance by combining solar PV panels with burned fly-ash tiles. Made from burning industrial waste, torched fly ash has special qualities that make it useful for architectural applications. These qualities include better thermal insulation, strengthened structural integrity, and high energy efficiency. Our test setup shows that when solar PV panels are combined with torched fly-ash tiles, power generation rises by 7% and surface temperature decreases by 3% when compared to standard panels. The enhanced PV efficiency is ascribed to the outstanding thermal insulation properties of fly ash tiles and their capacity to control panel temperature. To ensure longevity and safety in building applications, the tiles employed in this study had a water absorption rate of 5.37%, flexural strength of 2.95 N/mm2, and slip resistance at 38 km/h. Furthermore, we find improved structural resilience and lower cooling costs when up to 30% of the sand in floor tiles is replaced with torched fly ash, which makes this method especially appropriate for sustainable buildings. Key performance indicators that show how effective these tiles are in maximizing energy use in buildings include thermal emissivity (0.874), solar reflectance (0.8), and solar absorption (0.256). While supporting more ecofriendly building techniques, this study highlights the advantages of utilizing burned fly ash in solar PV systems: enhanced power generation and thermal comfort. The main results open a greater potential for fly ash use in different building materials. The use of torched fly ash in building materials enhances thermal insulation and structural integrity while lowering cooling costs, making it an ideal choice for eco-friendly construction and highlighting the potential for further research into environmentally responsible, energy-efficient solutions.

Optimizing alkali-activated clay with rubber waste for sustainable earthen bricks: A comprehensive study

This study explores the potential of optimizing alkali-activated clay with rubber waste to create sustainable earthen bricks. The research addresses the environmental challenges associated with traditional cement-based construction materials by incorporating locally sourced calcined clay and recycled rubber tire waste. The experimental program involves testing different proportions of sand with calcined clay, varying sodium hydroxide (NaOH) concentrations, and integrating rubber content. The aim is to develop a material that balances environmental sustainability with improved mechanical and durability properties. The mechanical and microstructural properties of the resulting materials were evaluated through compressive and flexural strength tests, wetting and drying cycles, and advanced analysis techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that while the inclusion of rubber enhances certain properties such as reducing the unit weight and Structural Integrity During Wet-Dry Cycles, it adversely affects compressive and flexural strengths. This study highlights the importance of optimizing the balance between durability and mechanical strength to develop effective and sustainable construction materials.

Non-destructive testing for thickness measurement of the adhesive layer and defect detection in ceramic-metal bonded structures using THz waves

Ceramics, owing to their superior thermal barrier properties, are employed by bonding them to primary structures exposed to elevated temperatures, such as the external components of aircraft and spacecraft. However, when these bonded structures are subjected to thermal impact resulting from high-temperature environments or rapid temperature variations, issues such as debonding, crack formation, and degradation may ensue. These issues can significantly undermine the reliability of the structures, necessitating nondestructive testing (NDT) to monitor the condition of the adhesive layer before and after thermal impact. In this article, we evaluated the integrity of adhesive structures before and after thermal impact using Terahertz (THz) waves, which offer exceptional penetration and resolution for NDT of nonmetallic materials without causing damage to the structure. To achieve this, ceramic-metal bonded structures were mounted on a robotic arm, and scanning was performed over a 70 mm area at 1 mm intervals and 0.5° increments. The peak-to-peak time of the THz signal through the adhesive layer was calculated to determine the thickness distribution. Based on experimental results, the average thickness of the ceramic layer before thermal shock was measured at 9.48 mm (standard deviation: 0.03) and the average thickness of the adhesive layer was 0.234 mm (standard deviation: 0.03). Additionally, four suspected defect areas within the adhesive layer were identified. After thermal shock, the ceramic layer’s thickness decreased by an average of 0.02 mm (0.17%), resulting in an average thickness of 9.46 mm, and the adhesive layer’s thickness decreased by an average of 0.002 mm (0.99%), resulting in an average thickness of 0.232 mm. The four suspected defect areas were confirmed to be in the same locations before thermal impact. To validate the NDT method using THz wave, the ceramic-metal bonded structure was cut to identify debonding defects in the suspected areas. The difference between the thickness distribution obtained using the THz wave-based NDT and that measured using optical microscopy after cutting was 4.4%, confirming the accuracy of the THz wave-based method for defect detection and thickness measurement.

Numerical Study on Heat Transfer and Thermal–Mechanical Performance of Actively Cooled Channel of All-Movable Rudder under Supercritical Pressure

The utilization of an actively cooled thermal protection system is widely recognized as an effective approach to decrease the temperature of components exposed to severe aerodynamic heating. In this study, two cooling schemes with different flow paths and structural configurations were proposed, and six cooling channel designs were developed by modifying the leading-edge details. A numerical analysis on the heat transfer and thermal–mechanical performance was conducted under actual flight conditions (30 km altitude, Mach 8). The results highlight an optimal design scheme that balances temperature control and minimized coolant flow rates. The channel flow field demonstrated its superiority by effective convective heat transfer and improved fluid mixing facilitated through recirculation zones and turbulence at the bends. Structural assessments showed that the optimal scheme not only provided better cooling but also preserved the structural integrity. Overall, the study offers a practical and effective thermal protection approach for air rudders subjected to severe heat.

The Tightening and Untightening Modeling and Simulation of Bolted Joints

Although bolted joints may appear simple and are easy to manipulate, they are challenging to model and analyze due to their complex structural patterns and statically indeterminate nature. Ensuring the structural integrity of these joints requires maintaining proper bolt preload and clamping force, which is crucial for preventing failures such as overload, excessive bearing stress, fatigue, and stripping caused by seizing or galling. Achieving the necessary clamping force involves carefully controlling the input tightening torque, which is divided into the pitch torque and the friction torques at the bolt or nut bearing surfaces and in the engaged threads. The resulting clamping force is critical for generating the required force within the bolt. However, the achieved bolt force depends on several factors, such as friction at the joint’s contact surfaces, grip length, and the relative rotation between the bolt and nut during tightening. Friction at the contact surfaces, particularly beneath the bolt head or nut and between the threads, consumes a significant portion of the applied tightening torque—approximately 90%. This paper explores the three existing bolt internal pitch, bearing, and thread friction torques that are generated by the external applied torque in a bolted joint, as well as their contributions and variations throughout a loading cycle composed of three phases: tightening, settling, and untightening. An analytical model is developed to determine these torque components, and its results are compared with those obtained from finite element (FE) modeling and experimental testing from previous studies. Finally, this study examines the torque–tension relationship during bolt tightening, offering insights into the required accuracy of bolt and clamped member stiffness. The bolt samples used in this study include M12 × 1.75 and M36 × 4 hex bolts.

Slope Stability Analysis of Open-Pit Mine Considering Weathering Effects

Weathering processes gradually alter the physical and mechanical attributes of slope materials, weakening the structural integrity and stability of slopes. This paper presents an in-depth analysis of slope stability in an open-pit mine, emphasizing the pivotal role of weathering effects in determining slope stability. To accurately capture the impact of weathering on slope stability, a comprehensive analysis model was developed, incorporating field observations, laboratory testing, and numerical simulations. The effects of weathering on the mechanical properties of black shale were studied through extensive laboratory tests. The uniaxial compressive strength, shear strength, and modulus of elasticity significantly decreased with increasing weathering, indicating a heightened vulnerability to slope failure. The correlation function between mechanical parameters and weathering time was obtained, providing the basis for evaluating the stability of mine slopes. It was found that more severe weathering conditions were strongly correlated with elevated risks of slope failure, including landslides and collapses. Based on these findings, practical recommendations are provided for slope reinforcement and management strategies, aimed at mitigating slope failure risks and ensuring the safe and efficient operation of the mine. By incorporating weathering effects into slope stability analysis, mine operators can make informed decisions that account for the dynamic nature of slope materials and their susceptibility to weathering, thereby improving overall mine performance and safety.