Safety Engineering Research Articles

Numerical analysis of thermal mechanism in downward flame spread over inverted surfaces of discrete inclined solid fuels

This investigation is propelled by engineering challenges associated with heat transfer during fire incidents on inclined surfaces, such as those observed in pitched roof fires, which hold significant implications for fire safety engineering and energy conservation. Drawing inspiration from real-world fire dynamics, this study delves into the downward flame spread over inverted solid fuel surfaces across a range of inclination angles, bridging the gap between theory and practice. Detailed analysis of temperature distribution, flame characteristics, and gas-phase reactions reveals critical insights into the complex interplay governing heat behavior under these conditions. The observed reduction in flame thickness and standoff distance with increasing inclination underscores the influence of buoyancy-induced plumes. This work developed a dimensionless formula that accounts for both buoyancy-induced plumes and diffusion rates perpendicular to the fuel, successfully capturing the variation in flame thickness with inclination angles. Furthermore, our findings show that the average flame spread rate escalates with higher inclination angles, attributed to enhanced gas-phase reactions near the flame front that lead to intensified heat transfer and a subsequent increase in temperature within the solid phase. The study also uncovers a competitive mechanism between flame “jumps” and heat transfer to the unburned zone, causing an initial increase and then a decrease in flame spread rates with increasing discrete gap size at larger inclination angles. Conversely, at smaller inclination angles, flame progression halts as the discrete gap size increases, due to inadequate heat transfer to the adjacent discrete fuel, resulting in the cessation of flame spread. This study not only advances our understanding of the thermal processes underpinning flame spread in inclined configurations but also offers crucial insights for developing more effective fire protection strategies and thermal protection systems in engineering applications.

Sandwich probe temperature sensor based on In2O3-IZO thin film for ultra-high temperatures

High-temperature thin-film thermocouples (TFTCs) have attracted significant attention in the aerospace and steel metallurgy industry. However, previous studies on TFTCs have primarily focused on the two-dimensional planar-type, whose thermal sensitive area has to be perpendicular to the test environment, and therefore affects the thermal fluids pattern or loses accuracy. In order to address this problem, recent studies have developed three-dimensional probe-type TFTCs, which can be set parallel to the test environment. Nevertheless, the probe-type TFTCs are limited by their measurement threshold and poor stability at high temperatures. To address these issues, in this study, we propose a novel probe-type TFTC with a sandwich structure. The sensitive layer is compounded with indium oxide doped zinc oxide and fabricated using screen-printing technology. With the protection of sandwich structure on electrode film, the sensor demonstrates robust high-temperature stability, enabling continuous working at 1200 °C above 5 h with a low drift rate of 2.3 °C·h−1. This sensor exhibits a high repeatability of 99.3% when measuring a wide range of temperatures, which is beyond the most existing probe-type TFTCs reported in the literature. With its excellent high-temperature performance, this temperature sensor holds immense potentials for enhancing equipment safety in the aerospace engineering and ensuring product quality in the steel metallurgy industry.

Study of Large Strain OFDR Sensor Based on Inclined Transfer Structure

In the fields of structural health monitoring, civil engineering safety monitoring, aerospace and other fields, the key challenge is to increase the range of strain measurements to solve with the information monitoring of large strains. Reducing the strain sensitivity of the sensor is an important way to solve the problem of small sensor ranges. In this paper, the inclined transfer structure is proposed to achieve large strain distributed optical fiber sensing. When the fiber is axially stretched directly to fracture, the inclined transfer structure is used to increase the strain measurement range of the system. The theoretical relationship between the strain monitored by single mode fiber sensors and the matrix strain is established. It is experimentally verified that the inclined transfer structure using polypropylene material as the matrix achieves the strain measurement from 36667[Formula: see text][Formula: see text] at sensing spatial resolution of 8[Formula: see text]mm, 10[Formula: see text]nm wavelength tuning range of the laser source and [Formula: see text] inclined angle, obtaining a good linear fit of more than 0.99. One hour stability of less than 11[Formula: see text]pm is obtained, corresponding to the strain of 9[Formula: see text][Formula: see text].

Research Progress in Remote Sensing, Artificial Intelligence and Deep Learning in Hydraulic Structure Safety Monitoring

Ensuring the safety of hydraulic structure engineering is of paramount importance, as these infrastructures play a critical role in water management, flood control, and the provision of clean water for various human and ecological needs [...]

Thermo-pressure coupling model for gas hydrate depressurization exploitation in South China Sea

The sediment type in the “Shenhu” sea area of the South China Sea is mud sediment, with poor reservoir physical conditions, and the seabed is loose with a small pressure window. These conditions pose heightened safety challenges for the extraction of hydrates in this region. This study develops a multiphase flow model that accounts for the endothermic decomposition of hydrates and employs the finite difference method for its solution. Utilizing this model, the multiphase flow characteristics during depressurization extraction at a specific well in the “Shenhu” area are investigated. Building on this, the study analyses the impact of varying pump rates and geothermal gradients on multiphase flow properties, hydrate yield, and engineering safety. Based on the analytical findings, recommendations are proposed to balance hydrate production with engineering safety, effectively mitigating potential engineering accidents during depressurization extraction. The outcomes of this research offer technical guidance for the commercial exploitation of hydrates in the “Shenhu” area of the South China Sea, laying a foundation for future related studies.

1D -FNO - Residual convolutional neural network autoregressive prediction model for deep water wave train evolution based on high-order spectral (HOS) data

Accurate prediction of deep-water wave dynamics is essential for ocean engineering, meteorology, and maritime safety. Traditional physical models, though effective, face significant computational and time challenges with complex nonlinear dynamics. This study introduces an autoregressive prediction model using a one-dimensional adaptive Fourier Neural Operator-Residual Convolutional Neural Network (1D-FNO-ResNet) to enhance prediction accuracy. We developed a high-precision single-step prediction model capable of capturing wave characteristics such as height and fluid particle velocity. A fine-tuning training strategy based on multi-step prediction errors was proposed for autoregressive evolution. Performance comparisons between the ResNet and FNO-ResNet models were made under various fine-tuning steps. A correction model was also introduced to control error accumulation, improving autoregressive prediction steps. The model's generalization performance was validated with modulated and random wave trains under different conditions, optimizing predictive stability and accuracy. This approach demonstrates efficient 1D deep-water wave evolution prediction, offering a novel deep learning solution for wave dynamics prediction in ocean engineering, supporting wave energy conversion device design and optimization.

A new fire damage index to assess the vulnerability of immovable cultural heritage

The recurrent occurrence of devastating fires in cultural heritage constructions highlights the need for more studies focusing on the assessment of their fire vulnerability to support the development of adequate mitigation measures. To address the limitations of existing methods, this article introduces the Potential Fire Damage Index (PFDI) as a new approach. The PFDI is an indicator-based method that integrates twenty-one Fire Vulnerability Indicators (FVIs) into four categories with varying weights. The method is applicable to various types of heritage constructions and independent of national fire safety codes, which makes it a versatile tool for assessing fire vulnerability and estimating potential damage that can impact the cultural values of these structures. The article emphasizes the significance of the PFDI for preliminary identification of critical points in heritage constructions requiring vulnerability reduction measures, paving the way for subsequent more rigorous fire safety engineering analyses. The detailed criteria for assessing the FVIs are presented, and a case study illustrates the PFDI's applicability. The case study analyses a historic church in Portugal and evaluates its current conditions, as well as the impact of implementing certain measures to reduce fire vulnerability. To evaluate the robustness of the PFDI, its results were also compared with those of a well-established method in the literature.

Study on crack propagation characteristics of rocks with different lateral pressure based on joint monitoring of DIC and AE

During the process of rock failure, the characteristics of crack propagation affect the fracture characteristics and macroscopic mechanical behavior of rocks, indirectly affecting the safety and stability of rock engineering. In order to study the evolution characteristics of cracks during rock failure under different lateral pressure, based on an improved digital image correlation (DIC) and acoustic emission (AE) signal recognition method, a visual biaxial servo loading device was developed to conduct biaxial compression tests on mudstone with prefabricated cracks of the same inclination angle. The research results indicate that the stages of crack propagation include microcracks propagation, crack tip formation, stable macroscopic cracks propagation, and unstable macroscopic cracks propagation. As the lateral pressure increased, the initiation frequency of cracks decreased, the quantity of propagation decreased, and the propagation path shortened, indirectly increasing the bearing strength of rocks. The initiation stress, peak stress, and elastic modulus of pre-cracked rocks with lateral pressure ≤ 2 MPa were lower than those of pre-cracked rocks with lateral pressure > 3 MPa, with the minimum reduction amplitude of 14.1%, 21.2%, and 12.6%, respectively. As the lateral pressure decreased, the dispersion of the AE main frequency distribution increased and accelerated its downward expansion. The surface temperature curves of rocks were prone to fluctuations and rapid upward evolution characteristics corresponding to crack tip formation and crack propagation, respectively. The research results provide theoretical and engineering references for the mining of weak coal seams.

Tunnel construction worker safety state prediction and management system based on AHP and anomaly detection algorithm model

Tunnels represent complex, high-risk, and technically demanding underground construction projects. The safety of construction workers in tunnels is influenced by various factors, including physiological indicators, tunnel dimensions, and internal environmental conditions. Analyzing safety based solely on static factors is inadequate for modern tunnel engineering safety management requirements. To address this challenge, this paper provides a comprehensive analysis of factors impacting safety and employs the Analytic Hierarchy Process (AHP) to identify seven significant factors with high importance: body temperature, heart rate, internal temperature, internal humidity, CO concentration, chlorine concentration, and the relative positioning of personnel. Considering these factors essential for assessing worker safety, we introduce a novel model named Tunnel-APH-AD. For training models aimed at anomaly detection, we performed data augmentation and utilized four distinct machine learning models. Additionally, ensemble learning techniques were applied to aggregate the predictions from individual models, thereby enhancing the effectiveness of detecting safety states for tunnel workers. We also evaluated the performance of these models on out-of-distribution (OOD) samples to test their robustness and generalizability. The experimental results indicate that, under similar ventilation and tunnel conditions, the ensemble learning model exhibits superior overall performance compared to individual models, underscoring the effectiveness of model combination in improving the accuracy and reliability of safety alerts. Through experimental validation, this study provides interpretable, scalable, and scientifically generalized applications of machine learning theories in systems for tunnel construction worker safety alerts. These findings contribute to advancing safety management practices in tunnel engineering, enabling proactive and effective measures to mitigate potential risks and ensure the well-being of workers.

Research on Reform and Innovation of Teaching Models of Public Safety Education Programs in Higher Education

This paper combines the characteristics of higher education and the characteristics of the discipline of safety engineering to reform and innovate the teaching mode of public safety education courses. In the form of a teaching team, we jointly discuss and develop a set of innovative teaching mode including teaching plan, lecture form, after-school activities arrangement and other detailed steps, and formulate a detailed implementation plan including teaching experiment design, teaching practice selection, and effect return visit analysis.

Control Effectiveness: Metric Development and Application to Resilient Lunar Habitat Design

System safety engineering in its bare essence involves identifying, assessing, and mitigating, or controlling, hazards. Appropriate safety controls are selected using hazard reduction precedence principles, prior experience, or by assessing their impact on residual risk (together with other factors like cost). We propose a control effectiveness metric as one way to systematically and consistently evaluate potential safety controls individually and thereby facilitate selecting a shortlist of potential controls for subsequent integrated evaluation. The control effectiveness metric considers a safety control’s availability when needed, the probability that its design is adequate in addressing the targeted hazard, the probability that the design will be implemented as intended, and the relationship between the time it takes for the safety control to address its target hazard and the time before the hazard propagates. We demonstrated the use of our metric on a lunar habitat design using a physics-based habitat simulator. High control effectiveness and safety controls result in a habitat with high resilience, while low control effectiveness results in lower resilience.

Research Progress in Corrosion Behavior and Anti-Corrosion Methods of Steel Rebar in Concrete

The corrosion of steel rebars is a prevalent factor leading to the diminished durability of reinforced concrete structures, posing a significant challenge to the safety of structural engineering. To tackle this issue, extensive research has been conducted, yielding a variety of theoretical insights and remedial measures. This review paper offers an exhaustive analysis of the passivation processes and corrosion mechanisms affecting steel rebars in reinforced concrete. It identifies key factors such as chloride ion penetration and concrete carbonization that primarily influence rebar corrosion. Furthermore, this paper discusses a suite of strategies designed to enhance the longevity of reinforced concrete structures. These include improving the concrete protective layer’s quality and bolstering the rebars’ corrosion resistance. As corrosion testing is essential for evaluating steel rebars’ resistance, this paper also details natural and accelerated corrosion testing methods applicable to rebars in concrete environments. Additionally, this paper deeply presents an exploration of the use of X-ray computed tomography (X-CT) technology for analyzing the corrosion byproducts and the interface characteristics of steel bars. Recognizing the close relationship between steel bar corrosion research and microstructural properties, this paper highlights the pivotal role of X-CT in advancing this field of study. In conclusion, this paper synthesizes the current state of knowledge and provides a prospective outlook on future research directions on the corrosion of steel rebars within reinforced concrete structures.

Scaled experiment and numerical study on the effect of a novel makeup air system on smoke control in atrium fires

In the field of fire safety engineering, makeup air systems design for atriums is always a concern for researchers and engineers. A novel makeup air system integrating breathing zone and underfloor air supply (BUMS) was applied in the investigated atrium in this study. However, the flow rates proportional relationship of makeup air required for effective smoke control on each floor remains unclear. Scaled experiments and numerical simulations were carried out to address this problem in this study. The results show that the BUMS effectively controlled temperature, followed by visibility, with minimal impact on carbon monoxide (CO) concentrations. When the flow rate of makeup air was equal on each floor, the sizes of the safe evacuation passageways created by the BUMS on the third and fourth floors were not conducive to the safe evacuation of personnel. Based on the proportion of the CO concentration of each floor under natural ventilation, distribution proportions of makeup air flow rate were obtained. The effective action area was used to help determine the upper limit flow rate ratio for each floor. Calculation results revealed that when the flow rate distribution proportion for the first to fourth floors was 15 %, 27 %, 28 % and 30 %, respectively, the smoke control effectiveness has been improved. These findings are expected are expected to provide a theoretical basis for designing makeup air systems in atrium and large-space buildings.

Experimental Investigation of Runback Water Flow Behavior on Aero-Engine Rotating Spinners with Different Wettabilities

The accumulation of ice on the aero-engine inlet compromises engine safety. Traditional hot air anti-icing systems, which utilize bleed air, require substantial energy, decreasing engine performance and increasing emissions. Superhydrophobic materials have shown potential in reducing energy consumption when combined with these systems. Research indicates that superhydrophobic surfaces on stationary components significantly reduce anti-icing energy consumption by altering runback water flow behavior. However, for rotating aero-engine components, the effectiveness of superhydrophobic surfaces and the influence of surface wettability on runback water flow remain unclear due to centrifugal and Coriolis forces. This study investigates the runback water flow behavior on aero-engine rotating spinner surfaces with varying wettabilities in a straight-flow spray wind tunnel. The results demonstrated that centrifugal force reduces the amount of runback water on the rotating spinner compared to the stationary surface, forming rivulet flows deflected opposite to the direction of rotation. Furthermore, wettability significantly affects the flow characteristics of runback water on rotating surfaces. As the contact angle increases, the liquid water on the rotating spinner transitions from continuous film flow to rivulet and bead-like flows. Notably, the superhydrophobic surface prevents water adhesion, indicating its potential for anti-icing on rotating components. In addition, the interaction between rotational speed and surface wettability enhances the effects, with both increased rotational speed and larger contact angles contributing to higher liquid water flow velocities, promoting the rapid formation and detachment of rivulet and bead-like flows.

Research on the performance and application of waterproofing materials in tunnel engineering

Abstract With the rapid development of highway transportation, the volume and construction difficulty of tunnel engineering have been increasing year by yea. Many engineering problems are difficult to solve, among which leakage is one of them. Tunnel waterproofing materials are an important component of controlling leakage and ensuring the safety and reliability of tunnel engineering. This paper provides the types, characteristics, and applications of tunnel waterproofing materials in tunnel engineering. The classification of tunnel waterproofing materials is introduced, including grouting materials, geotextile materials, and waterproofing board materials. Then, the characteristics of each type of material are elaborated in detail, including durability, constructability, and environmental friendliness. Finally, combined with actual engineering cases, the application of these tunnel waterproofing materials in tunnel engineering is discussed. This paper aims to provide a reference for the design and construction of tunnel engineering, and to provide a theoretical and practical basis for the research and application of tunnel waterproofing materials.

Systems‐Theoretic Concept Design: An Intent Model for Early Concept Generation

AbstractThe complexity of engineered systems has grown leaps and bounds over the last forty years. One of the main challenges in modern engineering is managing this complexity, particularly as the pace of technological change continues to accelerate across industries. While most systems professionals agree, a viable early design concept is crucial to meeting stakeholders' needs and successfully scoping a development program, traditional early concept generation approaches focus on a design‐first approach, often glossing over an analysis of system intent and a synthesis of system goals and objectives. This tendency leads to an early focus on low‐level, highly‐granular design activities that focus on advanced technologies as design components instead of on the high‐level policy or desired emergence that the new system is being designed to achieve. To combat these shortcomings, this paper introduces a new framework for conceptualizing an early design for novel, complex systems in aerospace and defense that are employed as part of a portfolio‐of‐systems in an attempt to achieve a high‐level policy or portfolio‐level capability. It outlines an intent model for framing a new system's contribution to a portfolio‐level capability, and it posits a framework for delivering a new model for early design concepts while providing a foundation to extend system‐theoretic hazard and security analysis techniques to systematically analyze safety and security engineering challenges for the designs in the earliest possible phase of their lifecycle.

Experimental study on dynamic characteristics of shock train in an isolator with different types of incident shocks

The hypersonic mixed-compression inlet, operating in an off-design state, can be categorized into low-speed and over-speed regimes based on whether the external compression shock is incident into the internal flow channel. In this study, we investigate the movement process of the shock train within an inlet/isolator under both low-speed and over-speed conditions by generating various incident shocks using wedges installed in a direct-connected ground wind tunnel. Experimental investigations are conducted to examine the dynamic characteristics of the shock train in an isolator subjected to different types of incident shocks at an incoming Mach number of 2.7. The findings reveal that varying levels of backpressure resistance for the shock train are observed with different types of incident shocks. Through the movement trajectory of the shock train leading shock (STLS) and power spectral density analysis, it is found that unilateral incident shocks result in a more intense oscillation process for the shock train with a lower dominant oscillation frequency. The dynamic mode decomposition method identifies different oscillation structures within the unsteady shock train flow field and highlights that dominant mode energy primarily concentrates at the STLS, while its symmetry is influenced by the type of incident shock. Specifically, the symmetric bilateral incident shock tends to promote a higher degree of symmetry in the STLS structure while reducing its oscillation strength; however, when the STLS passes over the reflection point of the incident shock, the rapid upstream movement of the shock train still occurs in this situation, thereby inducing inlet unstart and compromising engine safety.

MEDIATING FINANCIAL AND HSE ROLES IN RISK MANAGEMENT IMPACT ON MYANMAR CONSTRUCTION SUCCESS

This study seeks to examine the effects of risk management strategies on the success of construction projects in Myanmar, a country with a rapidly expanding construction industry that has received little scholarly attention. Using a combination of traditional paper-based surveys and online questionnaires, a comprehensive dataset has been compiled for this study. The participants, which included project managers, project engineers, safety engineers, financial experts, and project proprietors, played a crucial role in providing diverse perspectives. From the initial sample of 500 questionnaires, a response rate of 84.6 percent yielded 397 valid responses. Using Smart PLS as a data analysis instrument, the study deconstructed risk management into its fundamental components: identification, analysis, response, and monitoring. In addition to the immediate effects, the study reveals the intermediate roles played by financial performance and Health, Safety, and Environment (HSE) issues. The findings indicate a correlation between the implementation of effective risk management strategies and the overall success of construction projects. The intermediate effect of financial performance and HSE performance strengthens the relationship between these variables. This research offers significant academic and practical insights by providing evidence-based strategies to improve risk management practices in Myanmar's rapidly developing construction industry.

Dual-axis fiber Bragg grating tilt sensor based on universal joint structure

Inclination angle measurement is widely used in fields such as infrastructure health, power engineering safety, and earthquake monitoring. In response to the problem that existing inclinometers based on the pendulum structure can only measure a single axial inclination angle, a dual-axis Fiber Bragg Grating (FBG) tilt sensor based on a universal joint structure is proposed. SolidWorks was used to establish a sensor model and conduct theoretical analysis. The structural parameters of the sensor were optimized using the control variable method. Based on the optimization results, a physical sensor was developed, and an inclination and temperature testing system was set up for performance testing. The results show that within a measurement range of ± 5°, the sensitivities of the X and Y axes of the sensor are 229.8 pm/° and 224.9 pm/°, respectively, with a resolution of approximately 4.4 × 10-4°. The tilt accuracy of the sensor is approximately 0.48°, and it exhibits good creep resistance and stability during long-term measurements, as well as temperature self-compensation capabilities. The research results provide a new reference for the development of similar dual-axis tilt measurement sensors.

Performance investigations on fluorine-rubber-tube-laying pumping wet shotcrete filled with microencapsulated phase change materials

The challenge of mitigating adverse climatic conditions is a critical issue that affects worker safety and operational efficiency in underground engineering. This study introduces an innovative approach using pumping wet shotcrete as an insulating material, incorporated with microencapsulated phase change materials (MPCMs) and filled within fluorine rubber tubes to address this concern. The MPCMs were synthesized via suspension polymerization, utilizing paraffin as the core material and modified SiO2-poly (lauryl methacrylate) as the shell material. To determine the optimal composition for practical application, an orthogonal experimental design was employed, complemented by comprehensive performance testing. The results indicated that a mix of 1375 kg/m3 of sand, 120 kg/m3 of ceramsite, and 1 g/cm of SiO2-MPCMs in each fluorine rubber tube having an inner diameter of 13 mm, provided the best balance between multiple properties. Notably, the insulation performance improved by 60–75 % compared to traditional pumping wet shotcrete, demonstrating a significant enhancement in thermal management capabilities. The findings contribute substantially to the field of thermal management in mines, presenting a novel technique that could be instrumental in improving safety and efficiency in deep underground operations.