Aug 2026· Proceedings of the Institution of Civil Engineers : Structures and buildings· pp. 1-13· 0 citations· 35 references
Abstract
To address fatigue failure, weld cracking and resonance in steel-frame pedestals caused by mechanical vibration, this study proposes a composite steel frame fabricated by integrating concave hexagonal negative-Poisson’s-ratio honeycomb structures with I-shaped steel, aiming to achieve the integrated structural function of load bearing and vibration damping. Bending and vibration tests are carried out on both conventional and composite steel frames to compare their static load-bearing characteristics and dynamic vibration-damping effects. Meanwhile, a finite-element model is established based on the Abaqus software platform to explore the regulation mechanism of honeycomb geometric parameters on the composite frame’s performance. Results show the composite frame realises ‘load-bearing–vibration-damping’ synergy, with yield strength basically consistent with conventional frames and excellent low-frequency vibration energy dissipation capacity. Honeycomb arrangement position and cell thickness mainly regulate load-bearing performance, while layer number and cell thickness have a significant impact on damping. After parameter optimisation, the maximum vibration level difference of the composite frame peaks at 62.81 dB, providing new design ideas and technical support for steel frame performance optimisation under low-frequency vibration environments.
Concrete-filled steel tube structures are widely used in industrial plants, large commercial buildings, infrastructure projects, antenna-supporting facilities, and electromagnetic-shielded spaces because of their strong mechanical performance and economic efficiency. Fire is a serious threat to structural safety. Under high temperatures, the load-bearing capacity and deformation control level of concrete-filled steel tube structures decrease significantly, while material strength loss, weakened interfacial bonding, and residual deformation develop simultaneously. These changes may not only reduce structural reliability but also affect the geometric stability required for antenna alignment and controlled electromagnetic environments. This paper focuses on the post-fire performance of concrete-filled steel tube structures and systematically discusses how high-performance fiber-reinforced composite wrapping and constraint enhancement can mitigate material degradation and preserve load-bearing capacity under extreme thermal stress. By analyzing the relationships among temperature-induced material deterioration, residual deformation, stiffness reduction, and reinforcement strategies, the study evaluates load-bearing capacity attenuation and deformation control in fire-exposed composite systems. The proposed optimization strategy provides technical support for post-disaster assessment, structural strengthening, and the safe reuse of steel–concrete composite structures in industrial buildings and electromagnetic functional facilities.
W. W. Li, W. Hou· Advanced Electromagnetics· 0 citations
To investigate the seismic performance of prefabricated concrete-filled circular steel tubular T-shaped column–composite beam frame joints, six full-scale prefabricated T-shaped joint frame specimens were designed and fabricated. The experimental variables included loading direction and axial compression ratio. Their failure modes, hysteretic behaviour, energy dissipation capacity and stiffness degradation were analysed through low-cycle reversed loading tests. The results showed that the specimens failed at the beam ends by way of a plastic hinge mechanism, and the failure mode satisfied the design requirements of ‘strong column–weak beam’ and ‘strong joint–weak component’. Within a specific range, increasing the axial compression ratio enhanced the specimens’ load-bearing capacity, energy dissipation capacity and ductility, while increasing the shear force in the joint core area. Under the same axial compression ratio, specimens loaded along the flange direction exhibited energy dissipation that was 92.0, 71.0 and 58.9% higher than those loaded along the web, with displacement ductility coefficients increasing by 6.0, 13.0 and 29.6%, respectively. Under seismic loading, the energy dissipation capacity and ductility performance of the T-shaped joints in the special-shaped concrete-filled steel tubular column frames were superior when loaded along the flange direction.
Zhan Zhang, Yuanyuan Cao, Liwei Wu et al.· Proceedings of the Instituti...· 0 citations
Spur gears are particularly vulnerable to vibration-induced resonance, noise production, dynamic stress concentration, and early fatigue failure while running at high speeds and under cyclic loading circumstances. The dynamic performance of conventional steel gears in sophisticated transmission systems is limited by their weak intrinsic damping capability, despite their high strength and wear resistance. This work uses advanced finite element modal and harmonic response analysis to examine the dynamic behavior and vibration attenuation properties of hybrid carbon-fiber-reinforced metal matrix composite (MMC) spur gears. Six material configurations were compared, including carbon-fiber/epoxy composite, stainless-steel-reinforced hybrids (CF/Epoxy/SS316 and CF/Epoxy/SS304), aluminum-reinforced hybrids (CF/Epoxy/Al6082 and CF/Epoxy/Al1050), and SCM420H steel. Equivalent orthotropic elastic formulations obtained using rule-of-mixtures homogenization were used to represent the composite materials. Mesh-independent models with realistic elastic support and frictional contact boundary conditions were used in ANSYS Workbench 2023 R1 for finite element simulations. The Block Lanczos solver was used for modal analysis in order to obtain natural frequencies and mode shapes. Harmonic response analysis was then used to assess resonance characteristics. Rayleigh damping implementation and characterization based on Dynamic Mechanical Analysis (DMA) were used to incorporate damping features. The findings show that, in comparison to traditional steel gears, all hybrid composites have noticeably higher natural frequencies and better damping characteristics. Because of its greater specific stiffness, Composite A (80% carbon fiber + 20% epoxy resin) showed the largest natural frequency range of 47.1–56.3 kHz. The optimum balance between lightweight properties, rigidity, and vibration attenuation was demonstrated by hybrid composites reinforced with aluminum. In comparison to steel gears, Composite C2 (CF/Epoxy/Al1050) achieved the highest damping ratio (ζ = 0.08) and lowered resonant amplitudes by around 40%. Additionally, a nearly 30% decrease in root fillet stress concentration was found by dynamic stress analysis, suggesting enhanced fatigue resistance and crack suppression capacity. Aluminum-based hybrids perform better because of their reduced density, better stiffness-to-weight ratio, less rotational inertia, and increased interfacial energy dissipation. The promise of hybrid carbon-fiber metal matrix composites for lightweight, vibration-resistant, and resonance-safe spur gear applications in cutting-edge automotive and industrial transmission systems is demonstrated by the developed orthotropic finite element framework.
Rishikesh Tike, N. Gautam, Vinaykumar S. Jatti et al.· Journal of Materials Science...· 0 citations
(English) 42CrMo steel is widely used in key load-bearing components subjected to low-speed, heavy-load, and cyclic service conditions, where fatigue failure is strongly governed by the surface residual stress state, microstructural stability, and surface integrity. URCP, combining static pressure and high-frequency vibration, can introduce severe plastic deformation and beneficial residual compressive stress, thereby significantly improving fatigue resistance. However, the coupled loading mechanism, microstructural evolution, and coordinated optimization of multiple surface performance indicators remain insufficiently understood. This thesis systematically investigates the surface strengthening mechanism and performance control of 42CrMo steel under URCP through mechanical modeling, thermo-mechanical simulation, experimental validation, microstructural characterization, and multi-objective optimization.
First, a composite loading mechanical model coupling static pressure and ultrasonic vibration, together with a three-dimensional rolling kinematic model, was established. A modified Johnson–Cook constitutive model suitable for high strain-rate impact conditions was developed, and an analytical model for the depth distribution of residual stress was derived. The results reveal that ultrasonic vibration generates periodic loading–unloading cycles in the contact zone, promoting cumulative plastic deformation and exponential decay of residual compressive stress along depth.
Second, a thermo-mechanically coupled finite element model incorporating the initial residual stress induced by turning was established. The effects of static pressure, amplitude, rotational speed, and feed rate on the evolution of stress field, temperature field, and plastic zone were systematically clarified. An energy response threshold was identified near 7 μm amplitude, at which the strengthening layer depth and peak compressive stress increase significantly while maintaining a low-temperature strengthening characteristic.
Third, comparative experiments between URCP and CR confirmed that URCP markedly enhances residual compressive stress, hardness, and surface morphology while improving load-bearing capacity and fatigue resistance. Rotating bending fatigue tests demonstrated a clear upward shift of the S–N curve and a significant extension of medium- and high-cycle fatigue life. Simulation and experimental results showed good agreement, with a maximum relative error below 10%.
Fourth, the cross-scale microstructural evolution under URCP was clarified. Grain refinement, increased dislocation density, and a higher proportion of low-angle grain boundaries were observed, leading to the formation of a stable gradient deformation layer. The grain orientation evolved from <101> toward <001> and <111>, revealing the intrinsic correlation between microstructural evolution and strengthening performance.
Finally, a multi-objective optimization algorithm integrating simulated annealing and particle swarm optimization (PSSAO) was proposed. Combined with response surface modeling, a stable Pareto front was obtained within 250 generations, enabling the coordinated optimization of residual stress, hardness, and surface roughness. The optimized parameter domain achieved residual compressive stress of −1283 to −1296 MPa, hardness of 60.9–61.6 HRC, and surface roughness of 0.120–0.156 μm, demonstrating the effectiveness of URCP for precise surface performance control.
(Català) L’acer 42CrMo s’utilitza àmpliament en components estructurals clau sotmesos a condicions de servei de baixa velocitat, càrrega elevada i esforços cíclics, on la fallada per fatiga està fortament determinada per l’estat de tensions residuals, l’estabilitat microestructural i la integritat superficial. El URCP, que combina pressió estàtica i vibració d’alta freqüència, pot induir deformació plàstica severa i introduir tensions residuals compressives beneficioses, millorant significativament la resistència a la fatiga. Tanmateix, el mecanisme de càrrega acoblada, l’evolució microestructural i l’optimització coordinada de múltiples indicadors de rendiment superficial encara no s’han comprès completament. Aquesta tesi investiga de manera sistemàtica el mecanisme de reforç superficial i el control del rendiment de l’acer 42CrMo sota URCP mitjançant modelització mecànica, simulació termo-mecànica, validació experimental, caracterització microestructural i optimització multiobjectiu.
En primer lloc, es va establir un model mecànic de càrrega composta que acobla pressió estàtica i vibració ultrasònica, juntament amb un model cinemàtic tridimensional de la trajectòria de laminació. Es va desenvolupar un model constitutiu Johnson–Cook modificat, adequat per a condicions d’impacte a alta velocitat de deformació, i es va derivar un model analític per a la distribució en profunditat de les tensions residuals. Els resultats mostren que la vibració ultrasònica genera cicles periòdics de càrrega–descàrrega a la zona de contacte, promovent l’acumulació de deformació plàstica i una atenuació exponencial de la tensió residual compressiva amb la profunditat.
En segon lloc, es va construir un model d’elements finits termo-mecànicament acoblat que incorpora l’estat inicial de tensions residuals induït pel tornejat. Es van aclarir sistemàticament els efectes de la pressió estàtica, l’amplitud, la velocitat de rotació i l’avanç sobre l’evolució del camp de tensions, el camp tèrmic i la zona plàstica. Es va identificar un llindar de resposta energètica proper als 7 μm d’amplitud, en el qual la profunditat de la capa reforçada i el pic de tensió compressiva augmenten significativament, mantenint alhora una característica de reforç a baixa temperatura.
En tercer lloc, experiments comparatius entre URCP i CR van confirmar que URCP millora notablement la tensió residual compressiva, la duresa i la morfologia superficial, així com la capacitat portant i la resistència a la fatiga. Els assaigs de fatiga per flexió rotativa van mostrar un desplaçament ascendent clar de la corba S–N i una prolongació significativa de la vida a fatiga en règims de mig i alt nombre de cicles. Els resultats numèrics i experimentals van mostrar una bona concordança, amb un error relatiu màxim inferior al 10 %.
En quart lloc, es va aclarir l’evolució microestructural multiescala sota URCP. Es van observar refinament de gra, augment de la densitat de dislocacions i una major proporció de límits de gra de baix angle, formant una capa estable de deformació en gradient. L’orientació cristal·logràfica va evolucionar de <101> cap a <001> i <111>, revelant la correlació intrínseca entre evolució microestructural i efecte de reforç.
Finalment, es va proposar un algoritme d’optimització multiobjectiu que integra recuit simulat i optimització per eixam de partícules (PSSAO). Combinat amb un model de superfície de resposta, es va obtenir un front de Pareto estable en 250 generacions, permetent l’optimització coordinada de la tensió residual, la duresa i la rugositat superficial. El domini òptim de paràmetres va assolir tensions residuals compressives de −1283 a −1296 MPa, dureses de 60.9–61.6 HRC i rugositats superficials de 0.120–0.156 μm, demostrant l’eficàcia del URCP per al control precís del rendiment superficial.
(Español) El acero 42CrMo se utiliza ampliamente en componentes estructurales clave sometidos a condiciones de servicio de baja velocidad, alta carga y esfuerzos cíclicos, donde la falla por fatiga está fuertemente determinada por el estado de tensiones residuales, la estabilidad microestructural y la integridad superficial. El URCP, que combina presión estática y vibración de alta frecuencia, puede inducir deformación plástica severa e introducir tensiones residuales compresivas beneficiosas, mejorando significativamente la resistencia a la fatiga. Sin embargo, el mecanismo de carga acoplada, la evolución microestructural y la optimización coordinada de múltiples indicadores de rendimiento superficial aún no se comprenden completamente. Esta tesis investiga de manera sistemática el mecanismo de fortalecimiento superficial y el control del rendimiento del acero 42CrMo bajo URCP mediante modelado mecánico, simulación termo-mecánica, validación experimental, caracterización microestructural y optimización multiobjetivo.
En primer lugar, se estableció un modelo mecánico de carga compuesta que acopla presión estática y vibración ultrasónica, junto con un modelo cinemático tridimensional del trayecto de rodadura. Se desarrolló un modelo constitutivo Johnson–Cook modificado, adecuado para condiciones de impacto a alta velocidad de deformación, y se derivó un modelo analítico para la distribución en profundidad de las tensiones residuales. Los resultados muestran que la vibración ultrasónica genera ciclos periódicos de carga–descarga en la zona de contacto, promoviendo la acumulación de deformación plástica y una atenuación exponencial de la tensión residual compresiva con la profundidad.
En segundo lugar, se construyó un modelo de elementos finitos termo-mecánicamente acoplado que incorpora el estado inicial de tensiones residuales inducido por torneado. Se aclararon sistemáticamente los efectos de la presión estática, amplitud, velocidad de rotación y avance sobre la evolución del campo de tensiones, el campo térmico y la zona plástica. Se identificó un umbral de respuesta energética cercano a 7 μm de amplitud, en el cual la profundidad de la capa endurecida y el pico de tensión compresiva aumentan significativamente, manteniendo al mismo tiempo una característica de fortalecimiento a baja temperatura.
En tercer lugar, experimentos comparativos entre URCP y CR confirmaron que URCP mejora notablemente la tensión residual compresiva, la dureza y la morfología superficial, así como la capacidad portante y la resistencia a la fatiga. Los ensayos de fatiga por flexión rotativa mostraron un desplazamiento ascendente claro de la curva S–N y una
To systematically investigate the effects of C-shaped and rectangular steel frames on the seismic performance of assembled composite shear walls, this paper, based on the validation of existing pseudo-static test results, employs ABAQUS software to establish refined finite element models, and carries out parametric analyses on C-shaped steel-frame composite shear walls (CSCSWs) and rectangular steel-frame composite shear walls (RSCSWs). With shear-span ratio, axial-load ratio, boundary frame steel plate thickness, and concrete strength grade as variables, a total of 28 numerical models are designed to systematically examine the influence laws of each parameter on bearing capacity, ductility, energy dissipation capacity, and failure modes, and to reveal the performance differences in the confinement mechanisms of the two cross-sectional types. The results indicate that: as the shear-span ratio decreases from 3.0 to 1.0, the bearing capacity increases by up to 171%, but the ductility drops by up to 43%, and the failure mode shifts from flexure-dominated to shear-dominated; increasing the steel plate thickness can simultaneously enhance bearing capacity and ductility, with the peak load increasing by up to 52% and cumulative energy dissipation by over 110%, the mechanism being the synergistic enhancement of the flexural contribution of the boundary frame and the passive confinement effect on the core concrete; increasing the axial-load ratio can improve bearing capacity by about 24%, but significantly impairs ductility and energy dissipation capacity, and it is recommended that the design axial-load ratio be controlled between 0.26 and 0.43; the concrete strength grade has a limited effect on bearing capacity, and as the strength increases, brittle characteristics emerge, leading to a ductility decrease of about 12%; therefore, provided that the strength requirements are met, enhancing the concrete strength grade should not be taken as the primary technical approach for improving the seismic performance of such structures. Comparing the two cross-sectional types, the rectangular cross-section, by providing more uniform and effective lateral confinement, exhibits superior bearing capacity, ductility, and energy dissipation to the C-shaped cross-section across the entire parameter domain, and its performance advantages are more pronounced under conditions of high axial-load ratio and large shear-span ratio.
Xuan Mo, Dan Liang, Tengfei Zhao et al.· Buildings· 0 citations
Lightweight and structural efficient floor system is critical in enhancing the performance, fuel efficiency and the payload capacity of the modern passenger buses. This paper demonstrates a numerical exploration of the bus floor thickness optimization and efficiency in terms of metallic and composite materials under practical service loading. An SML compliant S7 bus platform (BS-VI) was taken as a reference model and a simplified ladder frame supported floor domain, which symbolizes realistic seating areas, was created in ANSYS Workbench. To simulate realistic load transfer, static structural simulations were conducted with a gravity-based passenger loading with the use of seat-support locations. Candidate materials were tested within the range of 10 to 50 mm thickness. Performance was measured in terms of the total deformation and equivalent stress. The findings imply that the thickness was a very significant factor on the stiffness response and high-modulus carbon-fiber laminates offer great reduction in weight and acceptable levels of deformation relative to traditional metallic floors. The methodology combines realistic geometry, support conditions, passenger loading, and thickness variation within a single finite element model. The results help identify lightweight, strong, and cost-effective materials for bus floor design.
A. Mache, Tejas Kajari, Abdullah Shaikh et al.· EPJ Web of Conferences· 0 citations
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