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A novel joint with a splice lap was proposed, which was damage-control and repairable fully precast beam-column joint (DRBJ) connected by energy-dissipating connecting steel plates to remarkably diminish the residual displacement of an RC frame under strong earthquakes and ensure the rapid rehabilitation of the structure. Four one-half scale beam-column-joint specimens were designed and fabricated in different connection forms and lap lengths, and one of the specimens was loaded again under the same conditions after repair. Low cyclic loading tests on DRBJ were conducted to investigate their hysteresis curves and energy-dissipation capacities. The test results revealed that the plastic deformation of DRBJ was concentrated on connecting steel plates, while the residual displacement was small. The deformation and bearing capacities of the short-lap joint were higher than those of the long-lap junction, and the bearing, energy consumption, and deformation capacities of the DRBJ connected by strip plates were still superior to those of the DRBJ connected by the rectangular plates. The DRBJ showed satisfactory repairability and energy-dissipation capacity with the help of the strip plates. A simplified force–displacement model was established based on the analysis of the functioning mechanism of DRBJ. The calculated results of the rotational stiffness and the test results agree well, which can provide a reference for the design of this type of splice joint. [ABSTRACT FROM AUTHOR]

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The energy-dissipation mechanism of an external replaceable mild steel energy dissipater suitable for self-centering hybrid connections under repeated tensile and compressive loads was investigated. The effects of the slenderness ratio and energy consumption section diameter on the bearing ability, energy-dissipation capacity, displacement ductility and stiffness degradation of the dissipater were also evaluated. The research results showed that when the hysteretic curve of the energy-dissipation device is full, the slenderness ratio has a great influence on the overall performance of the energy-dissipation device. The ratio of the end diameter of the dissipater to the weakening section should not be less than 4/3. The energy-consuming devices have good-displacement ductility, up to 4.97. Simplified models of the dissipater-force mechanism were established. Two stress stages of the replaceable mild steel energy dissipater under cyclic tension–compression loading were defined. A parametric model of the hysteresis curve under cyclic tension–compression loading was established via theoretical calculations and experiments. [ABSTRACT FROM AUTHOR]

Horizontal storage tanks are integral to the petrochemical industry but pose significant risks during earthquakes, potentially causing severe secondary disasters. Current seismic designs predominantly assume rigid tank walls, which can lead to an underestimation of seismic responses. This study introduces a novel analysis method for assessing the dynamic response of flexible-walled horizontal storage tanks. By separating the liquid velocity potential into convective and impulsive components and integrating these with beam vibration theory, we developed a simplified mechanical model. A parameter analysis and dynamic response research were conducted using numerical methods. Results indicate that flexible tank walls amplify seismic responses, including liquid dynamic pressure peaks, base shear, and overturning bending moments, compared to rigid walls. Additionally, the impact of flexible walls is more pronounced in tanks with larger radii, aspect ratios, diameter–thickness ratios, and H/R ratios. These findings highlight the necessity for revised seismic design approaches that consider wall flexibility to enhance the safety and resilience of horizontal storage tanks. [ABSTRACT FROM AUTHOR]

In order to study the dynamic response of the LNG storage tank under the action of seismic load and the seismic isolation effect of the lead-core rubber bearing, this paper establishes the experimental storage tank model with reference to the structural form of the large-scale LNG storage tank, and the seismic response of the test tank is obtained using a shaking table test. Simplified mechanical models of non-isolated and isolated storage tanks are proposed and the seismic responses of the corresponding storage tanks are calculated using the Newmark-beta method. Under the action of seismic waves with different acceleration peaks, the results show that (a) more excitation directions of the seismic wave can lead to the greater acceleration and displacement response of the tank and (b) the isolation bearing has a damping effect on the acceleration response of the storage tank, but it has an amplifying effect on the displacement of the storage tank. Comparing the results of the simplified model and the shaking table test, it is found that the change trend of the acceleration response of the experimental results and simplified mechanical models is the same. The spectral characteristic curve of them is not large, which verifies the effectiveness of the simplified model. [ABSTRACT FROM AUTHOR]

In order to study the effect of liquid sloshing on the seismic response of horizontal storage tanks，based on the simplified mechanical model of horizontal storage tanks considering liquid sloshing，the numerical calculation method was used to compare and analyze the seismic response of the horizontal storage tank with and without consideration of liquid sloshing，and compared with the shaking table test data. The results of the study show that the calculation results of the seismic response of the simplified two‐particle mechanical model considering liquid sloshing are less than the single‐particle model.The sloshing of the liquid storage has a certain inhibitory effect on the seismic response of the horizontal storage tank，and the seismic response is reduced by about 10% to 40%. The calculation results of the two‐particle model considering liquid sloshing are closer to the test data，indicating that the simplified mechanical model considering liquid sloshing can more closely reflect the seismic response of the horizontal storage tank，while the single‐particle model calculation results are larger and the seismic design is more conservative [ABSTRACT FROM AUTHOR]

In order to study the dynamic response of the LNG storage tank under the action of seismic load and the seismic isolation effect of the lead-core rubber bearing, this paper establishes the experimental storage tank model with reference to the structural form of the large-scale LNG storage tank, and the seismic response of the test tank is obtained using a shaking table test. Simplified mechanical models of non-isolated and isolated storage tanks are proposed and the seismic responses of the corresponding storage tanks are calculated using the Newmark-beta method. Under the action of seismic waves with different acceleration peaks, the results show that (a) more excitation directions of the seismic wave can lead to the greater acceleration and displacement response of the tank and (b) the isolation bearing has a damping effect on the acceleration response of the storage tank, but it has an amplifying effect on the displacement of the storage tank. Comparing the results of the simplified model and the shaking table test, it is found that the change trend of the acceleration response of the experimental results and simplified mechanical models is the same. The spectral characteristic curve of them is not large, which verifies the effectiveness of the simplified model.

This paper presents a prioritisation procedure to rank reinforced concrete (r.c.) buildings that are part of a stock according to their seismic vulnerability, and to plan further verifications and retrofit interventions. The proposed approach is based on visual inspections, qualitative evaluation, and quantitative assessment. The qualitative evaluation is based on a new deficiency form, here presented, whereas the quantitative assessment is carried out through a simplified mechanical model, which provides a ratio of capacity to demand. This work thus proposes a combination of the qualitative and quantitative approaches aimed at prioritisation. In this way, specific limitations of each approach are overcome through the combination. The proposed procedure was applied to the r.c. school building asset managed by the municipality of Padova (Italy). After describing the main characteristics of the inspected stock, the paper discusses the most commonly observed vulnerability factors and the application of the procedure. The qualitative and quantitative approaches integrated each other quite well and showed a general good agreement. • We innovatively combine qualitative and mechanical methods for seismic assessment. • We update a form for qualitative evaluation for screening of vulnerability factors. • Qualitative method considers vulnerability factors neglected by mechanical models. • The expeditious method is able to catch peculiarities of each structure. • The method was applied to a real stock of r.c. school buildings in Padova (Italy). [ABSTRACT FROM AUTHOR]

In order to realize lightweight design of a high-bypass turbofan engine, topology optimization of vacuum structure on a wide-chord fan blade was carried out regarding mixed loading conditions as static strength, vibration and bird-strike. Without changing the leaf shape, relationship of performance indices on vacuum structure was analyzed with simplified mechanical model of loading conditions. Topology optimization designs were carried out according to the highly sensitive conditions. Vacuum structure layout of fan blade was constructed integrating the major load transfer paths in each design proposal. Performance indices of different fan blade structures were compared. Result shown that optimized fan blade can realize lightweight as well as meeting the strength design requirement. [ABSTRACT FROM AUTHOR]

The mechanical properties of woodceramics, which are new porous carbon materials utilizing the natural structure of wood, were investigated. The effects of burning temperature and amount of impregnated phenol resin on Young's modulus, compressive strength and fracture toughness were measured. The fracture morphology was then observed, and simplified mechanical models of the woodceramics were discussed to explain the mechanical properties. The fracture was initiated at the cell walls that were located in vertical direction against the applied stress. The effect of impregnated phenol resin on the Young's modulus and the compressive strength was reasonably explained by a wall-bending model. [ABSTRACT FROM AUTHOR]

In this study, a scale model of a liquefied natural gas (LNG) storage tank was designed to carry out a shaking table test, the main position of insulation layer on tank and the site effect were investigated under different ground motions. The test results show that there is an obvious interaction between the insulation layer and the liquid-solid coupling position of the storage tank, and the seismic response of the tank was related to the frequency of the ground motions, the site effect should be considered when analysing the seismic response of liquid-solid coupling structures. Based on the test results, a simplified mechanical model for the seismic design of LNG storage tanks that considered the insulation layer was constructed, and the simplified mechanical model was verified via a numerical simulation method. Moreover, based on the results of the 16 × 104 m3 LNG storage tank simplified mechanical model, the base shear and bending moment were reduced by 20%–25% on average, the acceleration and displacement of the inner tank wall were reduced by 40% on average after filling the insulation. In the seismic design of large scale LNG storage tanks, considering the damping effect of insulation is helpful to save design capital, and ignoring the damping effect of insulation will make the design conservative. [ABSTRACT FROM AUTHOR]

Based on potential fluid theory and soil model theory, this paper derived a simplified mechanical model for horizontal storage tanks considering soil-tank-liquid interaction (STLI), which can be used for seismic design of horizontal storage tanks. Then the paper studied the ground motion response of STLI and Non-STLI under different shear wave velocity. We find the seismic response of the horizontal storage tank is more severe after considering the STLI, and the main control targets such as the base shear force, overturning bending moment and sloshing wave height increase by 25%~58%. Moreover, the effects of soft and medium soft fields are more significant. (1) There are few papers or research reports on the effects of soil-storage-liquid interactions on the ground motion response of horizontal storage tanks in the published literature. In view of the seismic design of horizontal storage tanks, we propose that the influence of soil factors should be considered, and a simplified mechanical model considering soil-storage-liquid interactions can be deduced, which can be used for seismic design of horizontal storage tanks. (2) Then the paper studied the ground motion response of STLI and Non-STLI under different shear wave velocity. Research shows that the seismic response of the horizontal storage tank is more severe after considering the STLI, and the main control targets such as the base shear force, overturning bending moment and sloshing wave height increase by 25%~58%. (3) We verified the simplified mechanical model from two aspects: first, through comparative analysis with published papers, and second, through comparative with finite element numerical simulation models. [ABSTRACT FROM AUTHOR]