Structural Failure Research Articles

Blast response and protection level of concrete composite wall panels made with recycled tyre fibres in a cement matrix

This paper investigates the blast response and protection level of a new blast-resistance wall panels made of Recycled Tyre Fibres Concrete (RTFC) as an exterior protective layer compositely connected to a concrete wall through experiments and numerical modelling. RTFC is a novel sustainable cement-based versatile composite, made with recycled non-biodegradable material (tyre rubber particles) in the form of composite fibres in a cement matrix, with applications in blast and ballistic protection that features high dynamic properties. Three composite wall panels were constructed and subjected to blast loads generated by Advanced Blast Simulator (ABS). Three different loading scenarios, each with an intensity capable of causing complete structural failure, were applied. The blast wave characteristics, such as the imposed overpressure and impulse, were measured alongside the deflection of the specimens. The wall specimens could withstand the blast loads with minimal damage. No cracks were observed in the RTFC layer, with only minor cracks appearing on the concrete side of the wall. The protection performance of the wall specimens was examined following UFC guidelines, revealing their outstanding resistance to blast loads. Moreover, in line with these guidelines, the composite wall panel is eligible for a High Level of Protection (HLoP) classification. Finally, a Single Degree of Freedom (SDOF) analytical model was developed for the wall panel to determine the Dynamic Increase Factor (DIF) of RTFC. The analysis resulted in a DIF value of 1.5, which was then incorporated into the numerical models of the walls. The accuracy of the DIF was validated by comparing the numerical results with experimental data, confirming its reliability.

Modification of New Semiconductor Materials by Doping

In the era of information, people’s lives are inseparable from electronic equipments. Semiconductors are key materials for manufacturing electronic equipment, which can be applied in multiple fields such as integrated circuits, solar cells, and so on. However, pure semiconductors have a single property, which are difficult to meet the design and usage requirements of different electronic devices. To solve the problem, introducing heteroatoms for modification to make them have more suitable performance will be a good way. Good semiconductor performance generally relies on precise control of the doping process. Different types of semiconductor materials typically require specific doping techniques to improve its performance. Adding small amounts of heteroatoms to pure semiconductors can significantly improve their conductivity by forming p/n junctions or achieving specific functions. Doping technology has been widely used in the semiconductor manufacturing industry. It is of great significance for the manufacturing of chips, photovoltaics and other devices. At present, there are still many shortcomings in doping technology. It may come across the semiconductor structure failure caused by doping, or difficulty in meeting performance requirements for use. Thereofore, continuous research and improvement are still needed. This paper reviewed the applications and the doping techniques of various semiconductor materials including two-dimensional semiconductors and organic semiconductors. In addition, it also provides prospects for their related applications and development.

Failure analysis of multi-span masonry arch bridges using combination of point cloud data and three-dimensional numerical modeling

Historical structures, including historical bridges, are part of cultural heritage, conveying the traces and characteristic features of past civilizations. To protect historical structures, it is necessary to prepare their 3D photogrammetric documentation, determine detailed geometric and material properties and perform computer-aided structural analysis using appropriate modeling techniques. The aim of this study is to present an effective, reliable and fast multidisciplinary approach for the analysis of historical masonry bridges. The aforementioned approach was illustrated with an example of the historical Halilviran masonry arch bridge and its behavior under possible loadings. Terrestrial laser scanning (TLS) was used to determine the bridge geometry with high accuracy. Point cloud data obtained from TLS was simplified and a three-dimensional CAD-based solid model of the structure was created. The Halilviran Bridge case study summarized in this report was conducted to examine the technical feasibility of using la¬ser scanning technologies for obtaining as-built records for similar historic bridges. A secondary objective was to identify other applications of this technology, notably for other transportation structures, and use numerical methods to assess the seismic behavior and failure model of the bridge. The seismic behavior of the bridge was examined using a finite-element- based macromodeling technique. Nonlinear dynamic analyses were carried out subsequently to identify the most susceptible regions of the bridge. Interpretation of the results, presented in the form of contour plots illustrating tensile damage and maximum displacements, offered a comprehensive depiction of the seismic response across the entire bridge. The methodology employed in this investigation can be viewed as a robust framework for evaluating the seismic response and potential failure of historical structures.

Effect of temperature rise caused by fire on the physical and mechanical properties of concrete

In the past few years, several concrete constructions have suffered major fires, causing very significant damage to the structure. The fire resistance of concrete depends on some of its characteristics such as the nature of the components used for its formulation, permeability, water content and mechanical resistance. In the places most exposed to fire, all the coating can be expelled, which seriously threatens the bearing capacity of the construction. In addition, the financial loss due to repair over a long period can reach several million Euros. This paper presents the physical and chemical transformations caused by the increase in the temperature of concrete in the event of a fire. These transformations mainly have an effect on the microstructure, the mechanical properties and the thermal deformation of concrete. The two phenomena of flaking and spalling of concrete were also studied in order to know their origins and found the methods of preventive. Indeed, flaking can manifest itself explosively, and have significant consequences on the resistance of concrete. It thus reduces the cross-section of the structure and also decreases its bearing capacity, which leads to an increase in the risk of structural failure. The factors influencing the flaking phenomenon were also presented.

Optimization of polypropylene high-strength injection molding welding and interface structure analysis

Secondary injection molding is an effective method for joining polymer parts, where the weld interface plays a critical role in the overall performance of the part. This study discusses the influence of injection molding parameters on the interface strength of polypropylene and polypropylene (PP-PP) secondary injection molding and analyzes the welding interface structure. The injection molding parameters for PP-PP were optimized using the Taguchi method and the signal-to-noise ratio (S/N). The optimal injection molding parameters were determined to be a mold temperature of 120°C, injection temperature of 350°C, and injection speed of 100 mm/s. The interface tensile strength was measured at 33.42 MPa, corresponding to 98.1% of the tensile strength of the base material. Among these parameters, mold temperature has the greatest influence on the strength of the welding interface. Secondly, polarizing microscopy, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were employed to observe and analyze the crystal structure and fracture failure modes at the interface. The results indicate that elevated injection molding parameters promote the formation of crystal nuclei and spherulite growth at the secondary melt interface, with the spherulite size at the interface significantly affecting the interface strength. This study offers valuable reference for the welding of other polymers and fiber-reinforced materials.

Susceptibility of hydraulic structures to internal erosion: modeling of suffusion process

Internal erosion is a primary cause of hydraulic structure failure, manifesting as two key phenomena: piping erosion and suffusion. These processes differ in their geometrical and hydraulic boundary conditions, resulting in varying levels of failure risk. Piping erosion is the more hazardous and rapid process, often leading to immediate failure if not promptly addressed. In contrast, suffusion gradually alters the permeability of the medium, potentially culminating in failure after a prolonged period of development. In this study, we propose a model for suffusion based on Darcy’s law, Papamichos' erosion law, and Einstein's viscosity evolution relation. The model describes the temporal evolution of the average porosity in the porous medium, the concentration of eroded particles in the fluid, and the mass of particles eroded, while highlighting the impact of hydraulic and mechanical parameters, such as the erosion coefficient and maximum porosity, on this evolution. The numerical solution is obtained using the finite difference method, with the sample discretized into elementary layers. For discretization, an explicit off-centered scheme was adopted. The simulation results reveal that suffusion is strongly influenced by soil hydraulic and mechanical parameters, particularly the erosion coefficient (λ) and final porosity (Ømax).

Life Prediction and Reliability Evaluation of Reinforced Concrete Frame Structures Considering the Collision Response Under Earthquake Conditions

Firstly, in this study, we utilize the high-order element model (truss link model) simulation method in OpenSees (3.7.0) software and verify the feasibility of this method by comparing it with the shaking table test. Secondly, the structural dynamic response of adjacent structures with different performance levels, spacing, and layout forms under large earthquakes is analyzed, and the corresponding structural failure probability is studied. Furthermore, the life distribution within the design service life of the structure is predicted according to the nonparametric Kaplan–Meier estimation model. Finally, the reliability of adjacent structures is evaluated by using the joint engineering demand parameters. The analysis method of replacing the theoretical analysis based on engineering experience and certainty in the current specification with probability analysis is proposed, which provides a more reliable theoretical basis for decision-making regarding the reinforcement, maintenance, or demolition of structures in the later stage.

Brief communication: Stalagmite damage by cave ice flow quantitatively assessed by fluid–structure interaction simulations

Abstract. Mechanical damage to stalagmites is commonly observed in mid-latitude caves. Former studies have identified thermoelastic ice expansion as a plausible mechanism for such damage. This study builds on these findings and investigates the role of ice flow along the cave bed as a possible second mechanism in stalagmite damage. Utilizing fluid–structure interaction models based on the finite-element method, forces created by ice flow are simulated for different stalagmite geometries. The resulting effects of such forces on the structural integrity of stalagmites are analyzed and presented. Our results suggest that structural failure of stalagmites caused by ice flow is possible, albeit unlikely.

Analysis and evaluation of suitability of high-pressure dynamic constitutive model for concrete under blast and impact loading

Concrete demonstrates complex dynamic mechanical behaviors under the influence of blast or impact loads, and there are inherent limitations in experimental and theoretical methods when dealing with highly nonlinear problems. As computational technologies and mechanics continue to evolve, it is possible to conduct high-fidelity simulations of the transient response of concrete structures subjected to intense dynamic loads. Such simulations play a crucial role in revealing the propagation laws of stress waves, the progression of damage, the mechanisms of structural failure, and in conducting protective engineering design. An accurate concrete material model is essential for conducting numerical studies. This article reviews the development of high-pressure dynamic constitutive models for concrete in recent years from both experimental research and theoretical modeling perspectives, focusing on the analysis and evaluation of the modeling methods and main shortcomings of the equation of state(EOS), strength model, and damage model. Using single-element numerical simulations under a single loading path and numerical calculations of engineering cases under complex loading paths, a systematic analysis and comparison were conducted on the predictive capabilities of the HJC, RHT, KCC, and CSC models, as well as the newly developed Kong-Fang and Yan-Chen models. It pointed out the impact of high-pressure mechanical behavior of concrete and the cumulative effect of damage under hydrostatic pressure on the calculation results. Finally, a discussion was conducted on the inherent flaws, applicability, and research difficulties of local constitutive models of concrete in the finite element method. This provides a reference for the selection and research of constitutive models when conducting numerical analysis of the blast and impact resistance of concrete structures.

Constitutive modeling of thermo-chemical decomposition and thermo-mechanical deformation, coupled with transient heat conduction, in ablative matrix composite

Several thermal protection systems employ sacrificial composite layer that undergoes thermo-chemical decomposition in high-temperature environment. This results in the pyrolysis gas formation (endothermic reaction) that gets trapped inside the voids generated in the ablative matrix phase. These trapped gases apply pore pressure on the structure, along with the mechanical loading, thus significantly influencing the structure failure. A novel thermo-chemical (TC) decomposition and thermo-mechanical (TM) deformation-based coupled multi-physics formulation, applicable to ablative composite systems, is thus presented. A novel shrinkage expression, due to ablative matrix decomposition, is derived. The TC + TM coupled formulation is converted to stress update process, and its results are validated against the available experimental data. The proposed formulation is also converted to boundary value problem employing non-linear finite element framework (NL-FEM). The Jacobian matrices, for one- and two-dimensional cases, are systematically derived, and the proposed NL-FEM formulation is successfully verified against several benchmark problems.The transient heat conduction equation is finally coupled with the proposed TC + TM formulation (one-way coupling) thus enabling the analysis of more realistic situations where the constant heating rate assumption is not valid. The coupled formulation is finally implemented for several test cases and it is demonstrated that, it has a significant influence on pore pressure and porosity evolution (through pore volumetric strain) within the ablative matrix phase.

Microstructure and Mechanical Properties of Bimetallic Structure Fabricated through Wire Plus Arc Additive Manufacturing

This study investigates the fabrication and mechanical assessment of bimetallic structure (BMS) wall using wire plus arc additive manufacturing (WAAM) technology, employing stainless steel (SS) 304 and SS 308L SS filler wire. The usage of BMS is promoted due to the limitation faced during dissimilar welding of the SS grades. The high or improper melting of the interface will lead to elemental segregation, leading to structural failure. Producing seamless BMS plates will be an ideal replacement for dissimilarly welded joints. Notably, 308L SS demonstrates superior mechanical properties compared to 304 SS, exhibiting impressive tensile strength (TS) and exceptional ductility. BMS, constructed with 308L filler wire, closely matches these better mechanical attributes, making it an attractive choice for applications prioritizing mechanical performance. Furthermore, when compared to WAAM‐processed SS 304, BMS consistently outperforms in terms of TS while retaining remarkable ductility. This is due to the variation in the microstructure caused by complex thermal cycles. Hence, this research provides valuable insights into manufacturing and characterization of BMS, emphasizing the potential of WAAM‐processed BMS (SS 304/SS 308L) in engineering applications demanding superior mechanical properties while replacing dissimilar joints in the fields of aerospace, aviation, automobile, and power generation industries.

Hierarchical Analysis of Miombo Woodland Spatial Dynamics in Lualaba Province (Democratic Republic of the Congo), 1990–2024: Integrating Remote Sensing and Landscape Ecology Techniques

Lualaba Province, located in the southeastern Democratic Republic of the Congo (DRC), consists of five territories with varied dominant land uses: agriculture (Dilolo, Kapanga, and Musumba in the west) and mining (Mutshatsha and Lubudi in the east). The province also includes protected areas with significant governance challenges. The tropical dry forests that cover the unique Miombo woodland of Lualaba are threatened by deforestation, which poses risks to biodiversity and local livelihoods that depend on these forests for agriculture and forestry. To quantify the spatio-temporal dynamics of Lualaba’s landscape, we utilized Landsat images from 1990 to 2024, supported by a Random Forest Classifier. Landscape metrics were calculated at multiple hierarchical levels: province, territory, and protected areas. A key contribution of this work is its identification of pronounced deforestation trends in the unique Miombo woodlands, where the overall woodland cover has declined dramatically from 62.9% to less than 25%. This is coupled with a marked increase in landscape fragmentation, isolation of remaining woodland patches, and a shift toward more heterogeneous land use patterns, as evidenced by the Shannon diversity index. Unlike previous research, our study distinguishes between the dynamics in agricultural territories—which are particularly vulnerable to deforestation—and those in mining areas, where Miombo forest cover remains more intact but is still under threat. This nuanced distinction between land use types offers critical insights into the differential impacts of economic activities on the landscape. Our study also uncovers significant deforestation within protected areas, underscoring the failure of current governance structures to safeguard these critical ecosystems. This comprehensive analysis offers a novel contribution to the literature by linking the spatial patterns of deforestation to both agricultural and mining pressures while simultaneously highlighting the governance challenges that exacerbate landscape transformation. Lualaba’s Miombo woodlands are at a critical juncture, and without urgent, coordinated intervention from local and international stakeholders, the ecological and socio-economic foundations of the region will be irreversibly compromised. Urgent action is needed to implement land conservation policies, promote sustainable agricultural practices, strengthen Miombo woodland regulation enforcement, and actively support protected areas.

Unlocking the Impact of Phyto-bioactive Compounds against Neurodegenerative Disorders

Neurodegenerative disorders (NDs) are one of the prominent worldwide issues recently. Neurodegenerative disorders, like amyotrophic lateral sclerosis, Parkinson's disease, Alzheimer's disease, and Huntington's disease, are characterized by ongoing neuronal failure and loss of structure and function, which ultimately results in neuronal death. There are many established synthetic approaches to target pathogenesis of NDs and to mitigate it but having several challenges researchers are now focusing the significant use of plant derived bio-active constituents against several NDs which ultimately leads safer and potent results. Among these phyto-compounds such as carotenoids, essential oils, essential fatty acids, polyphenols, have attracted great animus due to their strong antioxidant and anti-incendiary properties effective against NDs. Considering these green compounds having significant role to manage various NDs as potent therapeutic approach, we reviewed the sources, application, safety and clinical aspects of phyto-constituents against NDs.

Time-dependent reliability analysis of flood defenses under cumulative internal erosion

Internal erosion is a significant cause of failure in dams, levees and other hydraulic structures. This article studies the time-dependent reliability of such structures under Backward Erosion Piping (BEP), a form of internal erosion in the foundation. First, a physics-based time-dependent piping failure model is presented. Second, a time-variant reliability analysis method is presented which allows to quantify how the reliability evolves over the years due to cumulative pipe growth over multiple flood events. Finally, these models are used to study the importance of time-dependence for reliability estimates of flood defenses in The Netherlands. The findings show that, particularly in coastal areas, incorporating time-dependence significantly reduces the computed failure probability. Reductions vary widely, ranging from a factor of 5 to more than 10 6 , depending on flood duration and levee properties. Therefore, reliability estimates for levees can be improved by incorporating time-dependent pipe development in the BEP failure model, and thereby contribute to avoiding unnecessary reinforcements.

Unraveling Magnet Structural Defects in Permanent Magnet Synchronous Machines—Harmonic Diagnosis and Performance Signatures

Rare-earth-based permanent magnets (PMs) have a vital role in numerous sustainable energy systems, such as electrical machines (EMs). However, their production can greatly harm the environment and their supply chain monopoly presents economic threats. Alternative materials are emerging, but the use of rare-earth PMs remains dominant due to their exceptional performance. Damage to magnet structure can cause loss of performance and efficiency, and propagation of cracks in PMs can result in breaking. In this context, prolonging the service life of PMs and ensuring that they remain damage-free and suitable for re-use is important both for sustainability reasons and cost management. This paper presents a new harmonic content diagnosis and motor performance analysis caused by various magnet structure defects or faults, such as cracked or broken magnets. The proposed method is used for modeling the successive physical failure of the magnet structure in the form of crack formation, crack growth, and magnet breakage. A surface-mounted permanent magnet synchronous motor (PMSM) is studied using simulation in Ansys Maxwell software (Version 2023), and different cracks and PM faults are modeled using the two-dimensional finite element method (FEM). The frequency domain simulation results demonstrate the influence of magnet cracks and their propagation on EM performance measures, such as stator current, distribution of magnetic flux density, back EMF, flux linkage, losses, and efficiency. The results show strong potential for application in health monitoring systems, which could be used to reduce the occurrence of in-service failures, thus reducing the usage of rare-earth magnet materials as well as cost.

Social workers’ support of the status quo: Results from a national survey

Summary Social work has an intimate and complex relationship with the systems that shape the social, political, economic, and environmental fabric of the United States. System justification theory helps explain why people are motivated to accept the status quo of systems and unequal social arrangements. This study examined the system-justifying beliefs of a national sample ( N = 516) of master’s-level social workers to better understand how beliefs about the status quo may shape job outcomes (e.g., burnout and satisfaction) and practice outcomes (e.g., goals, motivations, perceptions of clients, and endorsement of practice behaviors). Findings Ordinary least squares regression analyses adjusting for demographic characteristics indicated significant relationships with both practice outcomes and job outcomes. Higher system-justifying beliefs were associated with less social justice motivation, more practical motivation, less transformative practice goals, and less understanding of clients’ needs as symptoms of structural failures. However, higher system-justifying beliefs were also associated with more compassion satisfaction, less secondary trauma, and less emotional exhaustion. Applications Key interventions into the structural conditions of social work practice so that social workers rely less on system-justifying beliefs to cope with burnout and increase satisfaction are discussed. Examples include investments in support resources, workplace empowerment, increased discretion, and workload reduction. Cognitive and psychological interventions, specifically the development of critical consciousness and critical thinking, are also suggested.

Failure Modes in Orthopedic Oncologic Reconstructive Surgery: A Review of Imaging Findings and Failure Rates.

Limb salvage surgeries utilizing endoprostheses and allografts are performed for a variety of oncologic conditions. These reconstructions can fail and require revision for many reasons, which are outlined and classified into mechanical failures (soft tissue failures, aseptic loosening, structural failure), non-mechanical failures (infection, tumor progression), and pediatric failures (physeal arrest, growth dysplasia). Distinct radiologic and clinical findings define specific failure subtypes but are sparsely illustrated in the radiology literature. Specifically, an understanding of the organizational structure of the failure modes can direct radiologists' search for post-reconstruction complications, enhance an appreciation of their prognostic significance, and facilitate research by standardizing the language and conceptual framework around outcomes. The purpose of this review is to highlight the key radiologic findings and imaging studies of each failure mode in orthopedic oncologic reconstructive surgery in the context of risk factors, failure rates, prognosis and survival statistics, and clinical decision-making regarding chemotherapy, radiation, and revision surgery.

The Stability and Failure of Deep Underground Structures at Potash Mining Deposits

The Stability and Failure of Deep Underground Structures at Potash Mining Deposits

Mechanical‐performance deterioration of RC segment of shield tunnel under high corrosion degree and the transformation of eccentric‐failure mode

AbstractReinforcement corrosion in shield tunnel segments has an important impact on the structure's bearing capacity and failure mode. Generally, a shield tunnel structure is under small eccentric compression, but if the reinforcement corrosion develops sufficiently, then a transition occurs from small to large eccentric load state, thereby lowering the structural bearing capacity and endangering the safety of tunnel operation. In the study reported here, based on the compressive bending load characteristics of the shield lining structure, corrosion test columns with small eccentric loading were designed to simulate the actual force state of the tunnel lining, and the whole evolution process of their mid‐span strain, ultimate bearing capacity, and cracks under different corrosion degrees was analyzed. With increasing corrosion, the bearing capacity, concrete strain, and depth of the compressive zone of a test column decrease more and more rapidly, and at the maximum corrosion degree of 68.32%, the maximum reduction of bearing capacity is 53.23%. The tests show that the failure mode of a test column with high corrosion degree (≥46.25%) is transformed from small to large eccentric failure. Based on theoretical analysis of the normal section bearing capacity of reinforced concrete flexural members, a theoretical method is proposed for calculating the critical corrosion degree for the tunnel lining structure to transform from small to large eccentric failure. The theoretical calculation method is verified against finite‐element calculations, and the present research results offer theoretical support for the durability design and safety evaluation of shield tunnel lining structures.

System fragility analysis of highway bridge using multi-output Gaussian process regression surrogate model

This study presents a multi-output Gaussian process regression (GPR) surrogate model for seismic-fragility analysis of bridge structural systems. Multi-output GPR can model the correlations among multiple outputs, accuracy and stability are achieved with fewer training data, which reduces the computational cost of fragility analysis. Furthermore, the explainability of the constructed surrogate model is implemented by adopting an automatic relevance-determination (ARD) kernel in the GPR. The estimated hyperparameters can provide the contribution of the uncertainty of each input parameter to the outputs. The fragility analysis using the multi-output GPR surrogate model was verified by applying it to a seismic isolation highway bridge with multiple spans and a curved geometry. The effectiveness of the multi-output GPR was demonstrated by the construction of an accurate and stable surrogate model with 46 inputs and 28 outputs. The relative contributions of the uncertainties to the structural properties and input earthquake loads could also be understood. The fragility curves, at both the component and system levels, were appropriately obtained using a sufficient number of samples in a Monte Carlo calculation. Furthermore, the failure modes were evaluated, identifying which structural components contributed to the system failure. This enabled discussions on structural system failures from the viewpoint of the structural dynamic characteristics of the bridge and earthquake-load properties.