Load bearing capacity reduction of concrete structures due to reinforcement corrosion

Huapeng Chen,Jaya Nepal 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.4

Reinforcement corrosion is one of the major problems in the durability of reinforced concrete structures exposed to aggressive environments. Deterioration caused by reinforcement corrosion reduces the durability and the safety margin of concrete structures, causing excessive costs in managing these structures safely. This paper aims to investigate the effects of reinforcement corrosion on the load bearing capacity deterioration of the corroded reinforced concrete structures. A new analytical method is proposed to predict the crack growth of cover concrete and evaluate the residual strength of concrete structures with corroded reinforcement failing in bond. The structural performance indicators, such as concrete crack growth and flexural strength deterioration rate, are assumed to be a stochastic process for lifetime distribution modelling of structural performance deterioration over time during the life cycle. The Weibull life evolution model is employed for analysing lifetime reliability and estimating remaining useful life of the corroded concrete structures. The results for the worked example show that the proposed approach can provide a reliable method for lifetime performance assessment of the corroded reinforced concrete structures.

A Study on Auto-Processing Flexible Production Line for Mass Customized BPO Data Based on Multi-Agents

Huapeng Chen,JieLin 보안공학연구지원센터 2014 International Journal of u- and e- Service, Scienc Vol.7 No.5

Traditional Data Business Process Outsourcing (Data-BPO) centers are facing the challenge of a static workflow based on manual operation. They cannot adapt to fast-changing demands from customers, which is proving to be a bottleneck in the Data-BPO service. This problem can be resolved through a Data-BPO automated production line, based on the usage of multi-agent (MA) and ontology. Through the cooperation of MA and categorization of ontology, the flexible production line can meet various requirementsofmass-customized data orders from different industries, professions, transactions and classes with instantaneous response. A Data-BPO flexible workflow will beimplemented dynamically, securely, quickly and smoothly. Therefore, developing an auto-processing flexible production line can greatly promote the efficiency and competitiveness of BPO enterprises currently based mostly on manual data-processing stations or manual-input equipment.

Antinociceptive effects of oleuropein in experimental models of neuropathic pain in male rats

( Huayong Chen ),( Dandan Ma ),( Huapeng Zhang ),( Yanhong Tang ),( Jun Wang ),( Renhu Li ),( Wen Wen ),( Yi Zhang ) 대한통증학회 2021 The Korean Journal of Pain Vol.34 No.1

Background: The present investigation explored the therapeutic actions of oleuropein along with the possible signaling pathway involved in attenuating neuropathic pain in chronic constriction injury (CCI) and vincristine-induced neuropathic pain in male rats. Methods: Four loose ligatures were placed around the sciatic nerve to induce CCI, and vincristine (50 μg/kg) was injected for 10 days to develop neuropathic pain. The development of cold allodynia, mechanical allodynia, and mechanical hyperalgesia was assessed using different pain-related behavioral tests. The levels of H₂S, cystathionine-γ-lyase (CSE), cystathionine-β-synthase (CBS), orexin, and nuclear factor erythroid-2-related factor 2 (Nrf2) were measured in the sciatic nerve. Results: Treatment with oleuropein for 14 days led to significant amelioration of behavioral manifestations of neuropathic pain in two pain models. Moreover, oleuropein restored both CCI and vincristine-induced decreases in H₂S, CSE, CBS, orexin, and Nrf2 levels. Co-administration of suvorexant, an orexin receptor antagonist, significantly counteracted the pain-attenuating actions of oleuropein and Nrf2 levels without modulating H₂S, CSE and CBS. Conclusions: Oleuropein has therapeutic potential to attenuate the pain manifestations in CCI and vincristine-induced neuropathic pain, possibly by restoring the CSE, CBS, and H₂S, which may subsequently increase the expression of orexin and Nrf2 to ameliorate behavioral manifestations of pain.

Performance optimization of flexible a-Si:H solar cells with nanotextured plasmonic substrate by tuning the thickness of oxide spacer layer

Xiao, Huapeng,Wang, Jun,Huang, Hongtao,Lu, Linfeng,Lin, Qingfeng,Fan, Zhiyong,Chen, Xiaoyuan,Jeong, Chaehwan,Zhu, Xufei,Li, Dongdong Elsevier 2015 Nano energy Vol.11 No.-

<P><B>Abstract</B></P> <P>Plasmonic thin film solar cells deposited on periodically textured photonic crystal substrates have been extensively studied since the substantially enhanced light absorption. The reduction of parasitic absorption losses in the metal and spacer layers becomes one of the key issues to achieve high efficiency solar cells. Herein, plasmonic amorphous silicon (a-Si:H) flexible thin film solar cells with different thickness of oxide spacer layers are systematically investigated. An increase of the spacer layer thickness leads to an evolution in surface morphology of AZO and final devices. More intriguingly, the increase of spacer layer thickness reduces the absorption in Ag layer while induces more absorption in spacer layer. The highest light absorption in silicon layer is observed as applying 100nm spacer layer, which is further verified by electrical measurements. Our observations demonstrate a versatile and convenient route towards rational design of light harvesting nanostructure for high performance plasmonic solar cells based on a broad range of materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Amorphous silicon thin film solar cells are constructed on patterned substrates. </LI> <LI> The devices properties are studied as a function of spacer layer thickness. </LI> <LI> An increase of spacer layer thickness reduces the absorption loss of Ag layer. </LI> <LI> The device with 100nm spacer layer confines more incident light in silicon layer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Prediction of vibration and noise from steel/composite bridges based on receptance and statistical energy analysis

Quanmin Liu,Linya Liu,Huapeng Chen,Yunlai Zhou,Xiaoyan Lei 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.37 No.3

The noise from the elevated lines of rail transit has become a growing problem. This paper presents a new method for the rapid prediction of the structure-borne noise from steel or composite bridges, based on the receptance and Statistical Energy Analysis (SEA), which is essential to the study of the generation mechanism and the design of a low-noise bridge. First, the vertical track-bridge coupled vibration equations in the frequency domain are constructed by simplifying the rail and the bridge as an infinite Timoshenko beam and a finite Euler-Bernoulli beam respectively. Second, all wheel/rail forces acting upon the track are computed by taking a moving wheel-rail roughness spectrum as the excitation to the train-track-bridge system. The displacements of rail and bridge are obtained by substituting wheel/rail forces into the track-bridge coupled vibration equations, and all spring forces on the bridge are calculated by multiplying the stiffness by the deformation of each spring. Then, the input power to the bridge in the SEA model is derived from spring forces and the bridge receptance. The vibration response of the bridge is derived from the solution to the power balance equations of the bridge, and then the structure-borne noise from the bridge is obtained. Finally, a tri-span continuous steel-concrete composite bridge is taken as a numerical example, and the theoretical calculations in terms of the vibration and noise induced by a passing train agree well with the field measurements, verifying the method. The influence of various factors on wheel/rail and spring forces is investigated to simplify the train-track-bridge interaction calculation for predicting the vibration and noise from steel or composite bridges.

Elastic local buckling behaviour of corroded cold-formed steel columns

Nie Biao,Xu Shanhua,Hu WeiCheng,Chen HuaPeng,Li AnBang,Zhang ZongXing 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.48 No.1

Under the long-term effect of corrosive environment, many cold-formed steel (CFS) structures have serious corrosion problems. Corrosion leads to the change of surface morphology and the loss of section thickness, which results in the change of instability mode and failure mechanism of CFS structure. This paper mainly investigates the elastic local buckling behavior of corroded CFS columns. The surface morphology scanning test was carried out for eight CFS columns accelerated corrosion by the outdoor periodic spray test. The thin shell finite element (FE) eigen-buckling analysis was also carried out to reveal the influence of corrosion surface characteristics, corrosion depth, corrosion location and corrosion area on the elastic local buckling behaviour of the plates with four simply supported edges. The accuracy of the proposed formulas for calculating the elastic local buckling stress of the corroded plates and columns was assessed through extensive parameter studies. The results indicated that for the plates considering corrosion surface characteristics, the maximum deformation area of local buckling was located at the plates with the minimum average section area. For the plates with localized corrosion, the main buckling shape of the plates changed from one half-wave to two half-wave with the increase in corrosion area length. The elastic local buckling stress decreased gradually with the increase in corrosion area width and length. In addition, the elastic local buckling stress decreased slowly when corrosion area thickness was relatively large, and then tends to accelerate with the reduction in corrosion area thickness. The distance from the corrosion area to the transverse and longitudinal centerline of the plate had little effect on the elastic local buckling stress. Finally, the calculation formula of the elastic local buckling stress of the corroded plates and CFS columns was proposed.