Dynamic analysis of train-bridge interaction system with flexible car-body

Wang Kunpeng,Xia He,Xu Man,Guo Weiwei 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.9

Lighter vehicles are used in high-speed trains and urban rail transit trains, which leads to lesser stiffness of car-bodies, so car-bodyflexibility should be considered in dynamic analysis of the train-bridge system. In this paper, the vehicle model is established based onflexible multi-body dynamics, in which the car-body is simulated with an Euler beam, and the movement of the car-body is the superpositionof its rigid displacement and the generalized displacement of vibration mode of the Euler beam with free boundaries. The dynamicanalysis model of train-bridge model is established using the flexible car-body model. A case study is performed of an ICE3 train runningon a (48+80+48) m three-span continuous girder bridge. The calculated results show that the car-body flexibility has little influence onbridge responses and vehicle running safety indices, but great influence on car-body accelerations. It is necessary to consider the car-bodyflexibility, especially in studying the influence of additional bridge deformations on vehicle responses.

Recent advances of Na3V2(PO4)3 as cathode for rechargeable zinc-based batteries

Ding Kunpeng,Jiang Tian,Peng Jian,Wang Peng,Gou Wenshan,Xu Qingyu,Fan Qi,Wang Wei,Sun Yueming 한국탄소학회 2023 Carbon Letters Vol.33 No.4

Rechargeable zinc-based batteries (RZBs) with the advantages of high safety, low cost, abundant resources and environmental friendliness, are considered as advanced secondary battery systems that can be applied to large-scale energy storage. As an important cathode material for RZBs, NASICON-type Na3V2(PO4)3 (NVP) possesses three-dimensional and large-scale ion channels that facilitate the rapid diffusion of Zn2+, and has a higher average operating voltage compared with other vanadium-based compounds, thus exhibiting the possibility of realizing RZBs with high energy density. However, NVP still has some problems, such as poor electronic conductivity and spontaneous dissolution in aqueous solution. The sluggish kinetics of Zn2+ (de)intercalation in NVP and dendritic growth on the Zn anode also contribute to the poor rate performance and short cycle life of the batteries. In this review, optimization strategies for the electrochemical performance of RZBs with NVP as cathode are systematically elaborated, including modification of NVP cathode and optimization of electrolyte. Several mainstream energy storage mechanisms and analysis methods in this battery system are sorted out and summarized. On this basis, the development direction of NVP–RZB system is further prospected.

Phtotoelectrochemical water oxidation to H2O2 based on N-TiO2 derived from NH2-MIL-125 and in-situ application on degradation dye

Kunpeng Liu,Nan Wang,Jianhua Li,Fanglin Du,Baorong Hou,Ruiyong Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.128 No.-

Electrochemical two-electron water oxidation reaction (2e WOR) to produce H2O2 has been widely concerned. However, four-electron competition reaction causes the large overpotential and low productionrates of 2e WOR, which restrict its’ development and application. Herein, we prepared N-TiO2 derivedfrom NH2-MIL-125 by the hydrothermal combined with calcination method. We found that N-TiO2 asphotoanode exhibited the well properties of photoelectrocatalysis water oxidation, which gave an overpotentialof 630 mV at 1 mA cm2. The overpotentials of N-TiO2 was approximately 130 mV (at1 mA cm2) lower than NH2-MIL-125, and even lower than the previous reported TiO2, which may attributeto the increased oxygen vacancy with the calcination process and N doping. In addition, we investigatedthe degradation performance of the prepared catalysts to degrade methylene blue byphotoelctrocatalysis on-site the preparation of H2O2. It was shown that N-TiO2 performed high degradationefficiency (91%) and excellent stability. The possible mechanism was speculated due to theincreased oxygen vacancy and N doping. This work provides a new idea for photoelectrocatalysis wateroxidation materials and points out a new way for on-site H2O2 production for direct use

Seismo-ionospheric anomalies associated with Mw 7.8 Nepal earthquake on 2015 April 25 from CMONOC GPS data

Kunpeng Shi,Jinyun Guo,Xin Liu,Lu Liu,Xinzhao You,Fangjian Wang 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.4

To explore the ionospheric coupling mechanism, the total electron contents (TECs) and slant TECs (STECs) were processed from GPS sites in China, Nepal and India, and the singular spectrum analysis (SSA) method was introduced to investigate the seismic-ionospheric signals prior to the Mw7.8 Nepal earthquake on April 25, 2015. The results of pre-earthquake ionospheric anomaly show that there were obviously positive on 2nd day and negative anomalies on 14th day prior to the earthquake, respectively. The radius of anomalous area with a regular elliptical shape reached 2500 km and 2000 km in the above days respectively, which was close to the radius of Nepal earthquake. After excluding the moving effects of ionosphere hump, the investigation by the global ionosphere maps (GIMs) shows that a wide TEC abnormality appeared over the epicenter and conjugated region with the duration of 12 hr. Besides, the magnitude of TEC anomalies impending the shock, with its peaks happening at the midday (local time), was proportional to the number of days prior to the occurrence. By using the STECs within seismogenic zone, we further studied the coseismic ionospheric disturbance (CID) of Nepal earthquake. The results show that two modes of CID propagation velocity have been detected. Due to the TEC respond of Rayleigh wave, one mode had average propagating speed of 1.3 km/s in the near-field within 800 km, and gradually reaching up to 2.7 km/s in the far-field beyond 2000 km. Another mode had average propagating speed of 0.6 km/s only existing in the near-field, which was in accordance with the speed of shock acoustic waves. Besides, CID intensity presented the obvious directional difference. The ambient magnetic field around the epicenter made it easier for CID to spread in the southward direction, the plateau topography also prohibited the propagation of ionospheric disturbance, and most CID points were detected along the southeast direction of the epicenter which is consistent with the rupture propagation.

Numerical simulation in time domain to study cross-flow VIV of catenary riser subject to vessel motion-induced oscillatory current

Liu, Kun,Wang, Kunpeng,Wang, Yihui,Li, Yulong The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

The present study proposes a time domain model for the Vortex-induced Vibration (VIV) simulation of a catenary riser under the combination of the current and oscillatory flow induced by vessel motion. In this model, the hydrodynamic force of VIV comprises excitation force, hydrodynamic damping and added mass, which are taken as functions of the non-dimensional frequency and amplitude ratio. The non-dimensional frequency is related with the response frequency, natural frequency, lock-in range and the fluid velocity. The relatively oscillatory flow induced by vessel motion is taken into account in the fluid velocity. Considering that the added mass coefficient and the non-dimensional frequency can affect each other, an iterative analysis is conducted at each time step to update the added mass coefficient and the natural frequency. This model is in detail validated against the published test models. The results show that the model can reasonably reflect the effect of the added mass coefficient on the VIV, and can well predict the riser's VIV under stationary and oscillatory flow induced by vessel motion. Based on the model, this study carries out the VIV simulation of a catenary riser with harmonic vessel motion. By analyzing the bending moment near the touchdown point, it is found that under the combination of the ocean current and oscillatory flow the vessel motion may decrease the VIV response, while increase the excited frequencies. In addition, the decreasing rate of the VIV under vessel surge is larger than that under vessel heave at small vessel motion velocity, while the situation becomes opposite at large vessel motion velocity.

Vibration analysis of train-bridge system with a damaged pier by flotilla collision and running safety of high-speed train

Chaoyi Xia,Kunpeng Wang,Jiacheng Huang,He Xia,Lin Qi,Xuan Wu 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.1

The dynamic responses of a pier-pile-soil system subjected to a barge/flotilla collision are analyzed. A coupled highspeed train and bridge system with a damaged pier after barge/flotilla collision is established by taking the additional unevenness of the track induced by the damaged pier as the self-excitation of the system. The whole process of a CRH2 high-speed train running on the 6×32 m simply-supported PC (prestressed concrete) box-girder bridge with a damaged pier is simulated as a case study. The results show that the lateral displacements and accelerations of the bridge with a damaged pier are much greater than the ones before the collision. The running safety indices of the train increase with the train speed as well as with the number of barges in the flotilla. In flotilla collision, the lateral wheel/rail forces of the train exceed the allowable values at a certain speed, which influences the running safety of the trains.

Numerical simulation in time domain to study cross-flow VIV of catenary riser subject to vessel motion-induced oscillatory current

Liu, Kun,Wang, Kunpeng,Wang, Yihui,Li, Yulong The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.-

The present study proposes a time domain model for the Vortex-induced Vibration (VIV) simulation of a catenary riser under the combination of the current and oscillatory flow induced by vessel motion. In this model, the hydrodynamic force of VIV comprises excitation force, hydrodynamic damping and added mass, which are taken as functions of the non-dimensional frequency and amplitude ratio. The non-dimensional frequency is related with the response frequency, natural frequency, lock-in range and the fluid velocity. The relatively oscillatory flow induced by vessel motion is taken into account in the fluid velocity. Considering that the added mass coefficient and the non-dimensional frequency can affect each other, an iterative analysis is conducted at each time step to update the added mass coefficient and the natural frequency. This model is in detail validated against the published test models. The results show that the model can reasonably reflect the effect of the added mass coefficient on the VIV, and can well predict the riser's VIV under stationary and oscillatory flow induced by vessel motion. Based on the model, this study carries out the VIV simulation of a catenary riser with harmonic vessel motion. By analyzing the bending moment near the touchdown point, it is found that under the combination of the ocean current and oscillatory flow the vessel motion may decrease the VIV response, while increase the excited frequencies. In addition, the decreasing rate of the VIV under vessel surge is larger than that under vessel heave at small vessel motion velocity, while the situation becomes opposite at large vessel motion velocity.

Preliminary Report on the Selection of Cold and Drought Resistant Dwarfing Apple Rootstocks

Tingzhen Yang,Qian Wang,Jingdong Gao,Kunpeng Li,Feng Han,Jianbao Tian 한국원예학회 2008 한국원예학회 기타간행물 Vol.- No.-

Bioinformatic and integrated analysis identifies an lncRNA–miRNA–mRNA interaction mechanism in gastric adenocarcinoma

Yong Liao,Wen Cao,Kunpeng Zhang,Yang Zhou,Xin Xu,Xiaoling Zhao,Xu Yang,Jitao Wang,Shouwen Zhao,Shiyu Zhang,Longfei Yang,Dengxiang Liu,Yanpeng Tian,Weizhong Wu 한국유전학회 2021 Genes & Genomics Vol.43 No.6

Background lncRNAs–miRNAs–mRNAs networks play an important role in Gastric adenocarcinoma (GA). Identifcation of these networks provide new insight into the role of these RNAs in gastric cancer. Objectives Biological information databases were screened to characterize and examine the regulatory networks and to further investigate the potential prognostic relationship this regulation has in GA. Methods By mining The Cancer Genome Atlas (TCGA) database, we gathered information on GA-related lncRNAs, miRNAs, and mRNAs. We identifed diferentially expressed (DE) lncRNAs, miRNAs, and mRNAs using R software. The lncRNA–miRNA–mRNA interaction network was constructed and subsequent survival examination was performed. Representative genes were selected out using The Biological Networks Gene Ontology plug-in tool on Cytoscape. Additional analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) terms were used to screen representative genes for functional enrichment. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) were used to identify the expression of fve candidate diferential expressed RNAs. Results Information of samples from 375 cases of gastric cancer and 32 healthy cases (normal tissues) were downloaded from the TCGA database. A total of 1632 DE-mRNAs, 1008 DE-lncRNAs and 104 DE-miRNAs were identifed and screened. Among them, 65 DE-lncRNAs, 10 DE-miRNAs, and 10 DE-mRNAs form lncRNAs–miRNAs–mRNAs regulatory network. Additionally, 10 lncRNAs and 2 mRNAs were associated with the prognosis of GA. Multivariable COX analysis revealed that AC018781.1 and VCAN-AS1 were independent risk factors for GA. GO functional enrichment analysis found DE-mRNA was signifcantly enriched TERM (P<0.05). The KEGG signal regulatory network analysis found 11 signifcantly enrichment networks, the most prevailing was for the AGE-RAGE signaling pathway associated with Diabetic complications. Results of RT-qPCR was consistent with the in silico results. Conclusions The results of the present study represent a view of GA from a analysis of lncRNA, miRNA and mRNA. The network of lncRNA–miRNA–mRNA interactions revealed here may potentially further experimental studies and may help biomarker development for GA.

Theoretical and numerical investigation on impact noise radiated by collision of two cylinders

Yinggang Li,Tianning Chen,Xiaopeng Wang,Kunpeng Yu,Chao Zhang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.6

Impact noise characterized by high peak value and short duration is very common source of noise in the industries and in many casescan be summed up in the noise radiated by collision of two cylinders. In order to precisely predict the impact noise radiated by collisionof two cylinders, a modified theoretical prediction model was established based on the Palmgren’s cylinder contact empirical model andacoustics theory. Then a numerical simulation method combining the finite element method (FEM) and the transient boundary elementmethod (TBEM) had been presented to verify the modified theoretical model and further discuss the mechanism of impact noise. Boththe contact force and impact noise of collision cylinders by the modified theoretical model were compared with the numerical results aswell as the prediction results by the original theoretical model. It indicated that the results by modified theoretical prediction model are ingood agreement with the numerical results, indicating better prediction superior to the original model. The impact noise radiated by collisioncylinders is attributed to the rigid body acceleration. Furthermore, the experimental validations were conducted to verify the modifiedtheoretical prediction model and numerical simulation results.