| 1. |
- Jia, He, et al.
(författare)
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Optimization and economic analysis of distributed photovoltaic-energy storage system under dynamic electricity price
- 2021
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Ingår i: Taiyangneng Xuebao/Acta Energiae Solaris Sinica. - 0254-0096. ; 42:5, s. 187-193
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigated the influence of different dynamic electricity pricing schemes, energy storage capacity and unit capacity cost on the economics of PV-storage systems. The energy storage control stratety of improving the photovoltaic micro-grid self-consumption was adopted in this study. Taking an office building in Changsha as an example, the dynamic planning method was used to solve the system's best operating strategy and calculated the system' life cycle economy and PV self-consumption rate. The results showed that the system profitable area was increased by 87% for every 41.5% increase of dynamic electricity price. Moreover, the impact of energy storage capacity on system economics is greater than unit cost. The increase of dynamic electricity price is beneficial to increase the self-consumption of photovoltaic power generation, and the storage capacity and unit cost dominate the self-consumption of photovoltaic energy in different intervals.
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| 2. |
- Wang, Benxin, 1991, et al.
(författare)
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Fracture characteristics and the damage constitutive model of 3D printing undulating joint samples based on DIC
- 2022
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Ingår i: Gongcheng Kexue Xuebao/Chinese Journal of Engineering. - 2095-9389. ; 44:12, s. 2029-2039
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Tidskriftsartikel (refereegranskat)abstract
- Due to the influence of geological structures, various forms of joint structural planes are present in rock mass engineering. The undulating structural planes, such as a torsional fold surface, are unique geological structures. These structures affect the stability of rock masses and cause potential hazards to rock mass engineering. Because of their shape complexity, the research on the fracture and damage constitutive law of rock mass with undulating joints is not thoroughly conducted. Undulating joints with various dip angles were fabricated using three-dimensional printing technology. The uniaxial compression test and digital image correlation (DIC) technology were used to study the mechanical and fracture characteristics of undulating joint specimens. Based on the principle of fracture mechanics, an idea was proposed to use the DIC displacement field for solving the stress intensity factor (SIF: type one KI and type two KII) at the joint tips and to study the damage constitutive law. The results show that the upper limit of undulating joint damage to specimens is determined with 46.6% through the minimum strength analysis. The sensitivity of uniaxial strength to a joint dip angle of undulating joint specimen is greater than that of a straight joint specimen. The fracture initiation occurs near peak stress. The fracture process can be divided into the initiation and synchronous penetration of microcracks on the fracture path. Additionally, the fracture mode shows a combination of multiple tension and shear fractures. The SIF increases with loading at the prepeak stage, and the cracks propagate in shear fracture at the joint left and right tips in the postpeak stage because KII>KI under the same stress. The undulating joint damage to the specimen with the dip angle is in a sinusoidal curve form. The relationships between the total damage coupled by joint and load with strain are all “S” curves.
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| 6. |
- Wu, Hao Yu, et al.
(författare)
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Transient response analysis of tension-leg-platformfloating offshore wind turbine under tendon failure conditions
- 2020
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Ingår i: Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science Edition. - 1008-973X. ; 54:11, s. 2196-2203
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Tidskriftsartikel (refereegranskat)abstract
- The mooring load calculation module of the fully coupled dynamic simulation software FAST was recompiled, and the transient response of a tension-leg-platform floating offshore wind turbine (FOWT) named WindStar TLP system under tendon failure was numerically simulated using a time domain method, in terms of the coupled system of wind turbine, tension-leg-type support platform and tendons. The transient response of the key parameters, i.e., platform motions, nacelle accelerations and tensions in the remaining tendons under different wave directions in 50-year extreme condition were investigated. Results show that the transient response of platform motions, nacelle accelerations and tendon tensions under tendon failure are significant. The transient response of FOWT with the broken tendon in back waves is greater than that with the broken tendon in head waves. And when the broken tendon in back waves is aligned with the wave, the transient response of FOWT is the maximum. The safety factor for tendon system under tendon failure in 50-year extreme condition meets the requirements of specification constituted by American Bureau of Shipping (ABS), which verifies the survivability of this tension-leg-type FOWT.
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| 7. |
- Zhang, Di, et al.
(författare)
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Modeling of ship navigation risk field for the icebreaker escort operations based on an artificial potential field
- 2024
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Ingår i: Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University. - 1006-7043. ; 45:1, s. 119-128
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Tidskriftsartikel (refereegranskat)abstract
- To assess the risk of a ship colliding and getting stuck in ice accidents, this study aims to analyze and quantify the ship navigation risk for icebreaker escort operations concerning the mutual relationship between the icebreaker and the assisted ship following the icebreaker and that between the assisted ship and sea ice. We propose a concept and model of a ship navigation risk field under an icebreaker escort operation based on an artificial potential field, including the icebreaker and sea ice risk fields. The icebreaker risk field quantifies the collision risk level between the icebreaker and the assisted ship, while the sea ice risk field quantifies the level of collision risk between the assisted ship and sea ice. The model can calculate the safe following distance between the icebreaker and the assisted ship. Finally, based on the marshaling navigation data of the TianYou ship in the Arctic, 2018, a ship navigation risk field model for an icebreaker escort operation is constructed for simulation verification. Results show that the proposed model is feasible and practical, which can theoretically support safety research following the distance between the icebreaker and the assisted ship under the icebreaker escort operation.
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