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A magnet cold test bench (MCTB) is being developed to accommodate the PF1 and TF superconducting coils of the International Thermonuclear Experimental Reactor, ensuring that performance evaluations are conducted under the required vacuum and cryogenic conditions. As the primary load-bearing components, the magnet supports in the MCTB must withstand gravitational forces from the coils, thermal and significant electromagnetic loads during testing. Their structural integrity is thus critical to the safety and reliability of the test system. This study presents a systematic design and evaluation of the MCTB magnet supports. The results indicate that the supercritical helium-cooled magnet supports exhibit excellent thermal insulation performance, with total heat load through the support–coil interfaces for each coil significantly below the design threshold (⩽400 W). In addition, a multi-physics coupled simulation is conducted to evaluate the structural integrity of the key load-bearing components and bolts, confirming compliance with applicable design standards. A buckling analysis further verifies the structural stability of the major load-bearing elements under extreme loading conditions. Finally, the capacity of the supports to absorb impact from the potential vertical drop of the TF coil is evaluated based on energy conversion principles. The results show that the support structure can safely withstand a 1.3 mm drop of the TF coil. If the integrity of the MCTB cryostat shell is not considered, the structure can theoretically sustain a TF coil drop of over 14 mm. These drop analysis results also provide essential quantitative support for the safe installation of the TF coil prior to testing. The design and validation approaches proposed in this study offer valuable technical insights for the development of large superconducting coil support structures in future fusion devices.

Empirical vulnerability models are fundamental tools to assess the impact of future earthquakes on urban settlements and communities. Generally, they consist of sets of fragility curves that are derived from georeferenced post-earthquake damage data. Following the 2015 Nepal earthquake sequence, the World Bank, through the Global Program for Safer Schools, conducted a Structural Integrity and Damage Assessment (SIDA) of about 18,000 school buildings in the earthquake-affected area. In this work, the database is utilized to identify the main structural characteristics of the Nepalese school building stock. For the first time, extended SIDA school damage data is processed to derive fragility curves for the main structural typologies. Data sets for each structural typology are used for a Bayesian updating of existing fragilities to obtain regional models for Nepalese schools. These fragility estimates can be adopted to assess potential seismic losses of the school infrastructure in Nepal. Additionally, they can be used for calibrating loss assessment studies in the wider Himalayan region where the structural typologies are similar.

An efficient optimization design for the large and complex components of fusion reactors is crucial to address the engineering design requirements and further promote technical standardization. Based on research status, current engineering designs for fusion reactors have some deficiencies, such as time and energy wastage, inefficiency, and difficulties in covering the typical ‘multi-variable multi-objective’ design requirements. These are pressing and common problems that urgently need to be overcome. To deal with the aforementioned technical challenges, it is vitally important to design an efficient, precise, and normalized approach that is tailored for the development of future fusion reactors. Therefore, this paper proposes a process-oriented optimization design method, which involves Coupled external parameterized modeling, Experimental points design, Response surface optimization, and Structural integrity validation (CERS), to improve the currently inefficient design methods. And the vacuum cryostat, the largest and complex component of a tokamak, is taken as an example to present the basic procedures of CERS. Firstly, the functions, basic structures, load types, analysis methods, and verification criteria of the cryostat are presented in detail. Then, real-time data interaction between external global parametric variables and ANSYS via coupling is established by CERS, which achieves parametric modeling of the cryostat and efficient experimental point design and optimization analysis with multi-variables and multi-objectives in an automatic way. Subsequently, this study demonstrates the significance and sensitivity of various structural parameters of the cryostat from such objectives as maximum deformation, maximum equivalent stress, and total mass. And the optimal set of its structural parameters is obtained by establishing a mathematical optimization model. Finally, the structural integrity is verified. The results indicate that the optimized cryostat maintains a minimum safety margin of 23% and will not suffer fatigue damage under various load events during its service. Moreover, the nonlinear buckling load multiplier ∅ is 5.4, obtained by analyzing the load-displacement curve of the cryostat according to the zero-curvature criterion. This shows that the designed cryostat is stable enough. The proposed method is simple, efficient, and reliable, and can be applied to both the cryostat and other complex components of fusion reactors in engineering design fields. It has great value of practical technical reference and can further promote the standardization of engineering design technology for future fusion reactors.

Highlights The biomimetic honeycomb-like porous magnetic NiFe@N-doped carbon aerogel (NFNCA) was efficiently fabricated through chemical cross-linking, in situ growth, unidirectional freeze-drying, and pyrolysis carbonization. The synergistic effect arising from the 3D conductive networking structure, diverse heterogeneous interfaces, magnetic/dielectric multi-component, and multiple loss pathways of NFNCA endowed this carbon aerogel with outstanding impedance matching and electromagnetic wave attenuation performance. The NFNCA featured excellent microwave attenuation, real-time monitoring of structural integrity, infrared thermal stealth, thermal management, and flame retardancy capabilities. Biomass carbon-based aerogels derived from collagen protofibrils are gaining considerable attention in electromagnetic protection. However, achieving a well-designed microstructure, optimized magnetic and dielectric loss components, and integrated multifunctionality within a single material system remains a significant challenge. Herein, a three-dimensional (3D) hierarchically biomimetic honeycomb-like porous magnetic NiFe@N-doped carbon aerogel (NFNCA) is obtained via a simple strategy involving in situ growth, freeze-drying, and pyrolysis carbonization. Driven by the synergy of a 3D conductive networking structure, magnetic and dielectric multi-components, numerous heterogeneous interfaces, and diverse loss pathways, the optimized NFNCA exhibits exceptional electromagnetic wave attenuation capability, evidenced by a minimum reflection loss ( R L ) of −53.49 dB at 1.93 mm and an effective absorption bandwidth of 6.24 GHz (11.76–18.00 GHz). Furthermore, the exceptional radar stealth, infrared thermal stealth, thermal management, and flame retardancy characteristics of NFNCA render it a promising candidate for multiple applications in demanding environments. Interestingly, the 3D cross-linked conductive network of NFNCA can serve as strain sensors to detect changes in the internal structure of carbon aerogels. Hence, this work provides a feasible design strategy for developing lightweight, high-efficiency, and multifunctional biomass-based carbon aerogel electromagnetic wave absorbing materials for various application scenarios.

Clad rebar is one of the key structures of marine and construction services. Therefore, it is of great importance to acknowledge the mechanical property parameters of the composite region in the structural integrity evaluation of clad rebar. The different base materials of clad rebar (20MnSiV/316L steel, 35#/316L steel, 45#/316L steel, and 55#/316L steel) are researched in this study. The composite area is further refined, and simultaneously, a refinement model of the composite region of clad rebar is established. In view of the fact that a surface hardness experiment is quite easy to conduct, a proposed method consists of obtaining the mechanical property parameters of materials using the surface hardness test. The mechanical property parameters are acquired; moreover, the relationship between yield stress and surface hardness of the stainless steel clad rebar is set up. We used this method to acquire the mechanical parameters of a composite surface uneven area of clad rebar, and we established a mechanical parameters mathematics model of clad rebar, it is a significant basis for a structural integrity evaluation of cladding materials.

Abstract This review examines the evolution and current role of life cycle management for aircraft engines under the Engine Structural Integrity Program (ENSIP) framework. ENSIP has been instrumental in aviation by providing frameworks for damage tolerance, fracture control, and fatigue life evaluation in both military and commercial aircraft engines. The paper synthesizes the transition of ENSIP from traditional damage-tolerance and safe-life methodologies toward data-driven, computationally enhanced frameworks. The core novelty lies in the structured integration of ENSIP principles with advanced computational approaches, including finite-element modelling, artificial intelligence (AI), prognostics and health management, digital twin technologies, and hybrid frameworks. In addition, the review organizes these approaches into an ENSIP-centric taxonomy and qualitatively discusses their relative maturity, practical readiness, and existing research gaps for life-cycle decision support. Moreover, the review addresses persistent technical, operational, economic, and management challenges, offering context for future maintenance frameworks. Ultimately, by integrating conventional engineering with advanced digital technologies, this review underscores ENSIP’s dynamic contribution to improving aviation safety, advancing maintenance practices, and achieving higher standards of operational performance. Graphical Abstract Graphical Abstract Evolution of ENSIP in life cycle management of aircraft engines.

Background Cetobacterium somerae , a symbiotic microorganism resident in various fish intestines, is recognized for its beneficial effects on fish gut health. However, the mechanisms underlying the effects of C. somerae on gut health remain unclear. In this experiment, we investigated the influence of C. somerae (CGMCC No.28843) on the growth performance, intestinal digestive and absorptive capacity, and intestinal structural integrity of juvenile grass carp ( Ctenopharyngodon idella ) and explored its potential mechanisms. Methods A cohort of 2,160 juvenile grass carp with an initial mean body weight of 11.30 ± 0.01 g were randomly allocated into 6 treatment groups, each comprising 6 replicates (60 fish per replicate). The experimental diets were supplemented with C. somerae at graded levels of 0.00 (control), 0.68 × 10⁹, 1.35 × 10⁹, 2.04 × 10⁹, 2.70 × 10⁹, and 3.40 × 10⁹ cells/kg feed. Following a 10-week experimental period, biological samples were collected for subsequent analyses. Results Dietary supplementation with C. somerae at 1.35 × 10⁹ cells/kg significantly enhanced growth performance, intestinal development, and nutrient retention rate in juvenile grass carp ( P  < 0.05). The treatment resulted in increased intestinal acetic acid concentration and enhanced activities of digestive enzymes and brush border enzymes ( P  < 0.05). Furthermore, it reduced intestinal permeability ( P  < 0.05), preserved tight junctions (TJ) ultrastructural integrity, and increased the expression of TJ and adherens junctions (AJ) biomarkers at both protein and transcriptional levels ( P  < 0.05). Mechanistically, these effects may be correlated with enhanced antioxidant capacity and coordinated modulation of the RhoA/ROCK, Sirt1, and PI3K/AKT signaling pathways. The appropriate supplementation levels, based on weight gain rate, feed conversion ratio, the activity of serum diamine oxidase and the content of lipopolysaccharide, were 1.27 × 10⁹, 1.27 × 10⁹, 1.34 × 10⁹ and 1.34 × 10⁹ cells/kg, respectively. Conclusions C. somerae improved intestinal digestive and absorptive capacity of juvenile grass carp, maintained intestinal structural integrity, and thus promoted their growth and development. This work demonstrates the potential of C. somerae as a probiotic for aquatic animals and provides a theoretical basis for its utilization in aquaculture.

Non-destructive testing (NDT) methods have been widely used for damage examination and structural maintenance, e.g., detecting and repairing fatigue cracks. In-service inspections help increase fatigue reliability by providing new information for updating structural failure probability and making repair decisions. However, these benefits are often compromised by uncertainties associated with inspection methods. Sometimes, existing cracks may not be identified, and positive inspection indication may actually not exist. It is of great interest to consider the influence of inspection uncertainty in maintenance optimization, because the benefits and costs of maintenance are affected by inspection decisions (e.g., inspection times and methods), which are subjected to inspection uncertainty. The influence of inspection uncertainty on maintenance optimization has not been explicitly and adequately covered in the literature. In this paper, the problem has been investigated by probabilistic modelling of the qualities of inspection methods via probability of detection (PoD) functions. A new PoD function is proposed to characterize the inspection quality when inspection uncertainty is neglected. Optimum inspection decisions are derived by the objective of maximizing lifetime reliability index under two scenarios (considering and not considering inspection uncertainty). The effectiveness index of a planned inspection is defined based on the max reliability indexes under the two scenarios. It is shown that the max lifetime reliability index generally deceases when inspection uncertainty is considered. Inspection uncertainty may have little influence on the lifetime reliability index, depending on the planned inspection time. The effectiveness index of a planned inspection increases with the decrease in the mean detectable crack size. However, inspection uncertainty can result in significant increases in expected life cycle costs and maintenance costs.

The airframe structures of most fighter aircraft in the Royal Malaysian Airforce have been in service for 10 to 20 years. The effect of fatigue loading, operating conditions, and environmental degradation has led to the structural integrity of the airframe being assessed for its airworthiness. Various NDT methods were used to determine the current condition of the aircraft structure after operation of beyond 10 years, and their outcomes are summarized. In addition, although there are six critical locations, the wing root was chosen since it has the highest possibility of fatigue failure. It was further analyzed using simulation analysis for fatigue life. This contributes to the development of the maintenance task card and ultimately assists in extending the service life of the fighter aircraft. Using the concept of either safe life or damage tolerance as its fatigue design philosophy, the RMAF has adopted the Aircraft Structural Integrity Program (ASIP) to monitor the structural integrity of its fighter aircraft. With the current budget constraints and structural life extension requirements, the RMAF has embarked on the non-destructive testing method and engineering analysis. The research outcome will enhance the ASIP for other aircraft platforms in the RMAF fleet for its structure life assessment or service life extension program.

Pipeline welding is an integral part of oil and gas exploration industries. Often the welded joint failures were due to lack of weld quality, improper heat treatment and even poor workmanship. Further, the use of new material in pipeline industry puts focus on a better understanding of qualifying requirements of welding for reducing the failures in future. This necessitates the need for development and design of suitable welding fluxes for joining these materials. In this paper an attempt is made to study the effects of submerged arc welding fluxes on weldability as well as structural integrity issues in pipeline steels. Physicochemical and thermophysical properties of submerged arc fluxes widely affects the mechanical behaviour of pipeline steels. This paper presents an overview of the role of welding parameters, flux composition, cooling rate, slag behaviour and physicochemical properties of slag on final welded joint properties such as tensile strength, impact toughness etc. during submerged arc welding.