An Experimental and Modeling Study on Vibro-Acoustic Response of Double-Walled Steel Cylindrical Shells

Xianzhong Wang,Li Chen,Ning Li,Yu Xia,Ye-Ping Xiong 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.4

Based on precise transfer matrix method (PTMM), the analytical model of the double-walled steel cylindrical shell was setup by taking into account of the annular plate and interlayer water. Under the linear sweep frequency excitation or the fi xed frequency excitation, an experimental model of the double-walled steel cylindrical shell has been designed, which is performed to gain the natural frequencies, forced vibration in air and water, underwater acoustic radiation. The analytical model was established to calculate natural frequencies, vibration acceleration level and sound pressure level and compare with the relevant experimental results. The compared results show that analytical results coincide with the experimental value and prove that the analytical model established by PTMM is reliable and credible. Meanwhile, the forced vibration behaviour of measuring positions at inner and outer shells was investigated both theoretically and experimentally. Eff ects of diff erent types of external excitations on the vibration and sound radiation of the double-walled cylindrical shell are discussed. As to acoustic radiation, the acoustic excitation plays a leading role in the low-frequency range. The force excitation is a major contributor in middle-high frequency range conversely.

Vibro-acoustic modelling of immersed cylindrical shells with variable thickness

Wang, Xianzhong,Lin, Hongzhou,Zhu, Yue,Wu, Weiguo The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

Based on the Precise Transfer Matrix Method (PTMM), the dynamic model is constructed to observe the vibration behaviour of cylindrical shells with variable thickness by solving a set of first-order differential equations. The free vibration of stiffened cylindrical shells with variable thickness can be obtained to compare with the exact solution and FEM results. The reliability of the present method of free vibration is well proved. Furthermore, the effect of thickness on the vibration responses of the cylindrical shell is also discussed. The acoustic response of immersed cylindrical shells is analyzed by a Pluralized Wave Superposition Method (PWSM). The sound pressure coefficient can be gained by collocating points along the meridian line to satisfy the Neumann boundary condition. The mode convergence analysis of the cylindrical shell is carried out to guarantee calculation precision. Also, the reliability of the present method on sound radiation is verified by comparing with experimental results and numerical results.

Vibro-acoustic modelling of immersed cylindrical shells with variable thickness

Wang, Xianzhong,Lin, Hongzhou,Zhu, Yue,Wu, Weiguo The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.-

Based on the Precise Transfer Matrix Method (PTMM), the dynamic model is constructed to observe the vibration behaviour of cylindrical shells with variable thickness by solving a set of first-order differential equations. The free vibration of stiffened cylindrical shells with variable thickness can be obtained to compare with the exact solution and FEM results. The reliability of the present method of free vibration is well proved. Furthermore, the effect of thickness on the vibration responses of the cylindrical shell is also discussed. The acoustic response of immersed cylindrical shells is analyzed by a Pluralized Wave Superposition Method (PWSM). The sound pressure coefficient can be gained by collocating points along the meridian line to satisfy the Neumann boundary condition. The mode convergence analysis of the cylindrical shell is carried out to guarantee calculation precision. Also, the reliability of the present method on sound radiation is verified by comparing with experimental results and numerical results.

Preparation and properties of Al-Al2O3 metal ceramics via powder metallurgy methods

Jieguang Song,Xiuqin Wang,Lin Chen,Cailiang Pang,Jia Zhang,Weiguo Shi,Songlin Guo,Xianzhong Wang,Ruihua Wang 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.1

Metal ceramics are outstanding new engineering materials that offer the advantages of both ceramics and metals. In this study,Al-Al2O3 metal ceramics were prepared through powder metallurgy methods, and the densification and properties of theprepared metal ceramics were investigated to gain insights into the preparation of high-performance cermet materials. Resultsrevealed that as the forming pressure was increased, the relative density of the ceramics increased, whereas their electricalresistivity decreased. The relative density increased with increasing sintering temperature up to 700 oC and decreased beyond700 oC, whereas the electrical resistivity exhibited an opposite trend. The relative density increased with increasing Al content,whereas the electrical resistivity displayed an opposite trend. Under optimal technological parameters of 700 oC sinteringtemperature, < 20MPa forming pressure, and 75 wt% Al content, Al-Al2O3 metal ceramics with a high relative density(97.52%) and a low electrical resistivity (101.34 Ω·m) were successfully prepared.

Flexural behavior of steel storage rack base-plate upright connections with concentric anchor bolts

Xianzhong Zhao,Zhaoqi Huang,Yue Wang,Ken S. Sivakumaran 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.3

Steel storage racks are slender structures whose overall behavior and the capacity depend largely on the flexural behavior of the base-plate to upright connections and on the behavior of beam-to-column connections. The base-plate upright connection assembly details, anchor bolt position in particular, associated with the high-rise steel storage racks differ from those of normal height steel storage racks. Since flexural behavior of high-rise rack base connection is hitherto unavailable, this investigation experimentally establishes the flexural behavior of base-plate upright connections of high-rise steel storage racks. This investigation used an enhanced test setup and considered nine groups of three identical tests to investigate the influence of factors such as axial load, base plate thickness, anchor bolt size, bracket length, and upright thickness. The test observations show that the base-plate assembly may significantly influence the overall behavior of such connections. A rigid plate analytical model and an elastic plate analytical model for the overall rotations stiffness of base-plate upright connections with concentric anchor bolts were constructed, and were found to give better predictions of the initial stiffness of such connections. Analytical model based parametric studies highlight and quantify the interplay of components and provide a means for efficient maximization of overall rotational stiffness of concentrically anchor bolted high-rise rack base-plate upright connections.

Identification and Functional Characterization of R3 MYB Transcription Factor Genes in Soybean

Shucai Wang,Jinsong Pang,Hongwei Xun,Zhibing Zhang,Yunxiao Zhou,Xueyan Qian,Yingshan Dong,Xianzhong Feng,Bao Liu 한국식물학회 2018 Journal of Plant Biology Vol.61 No.2

In Arabidopsis, trichome formation is regulatedby a MYB-bHLH-WD40 (MBW) transcriptional activatorcomplex, which can activate the expression of GLABRA2(GL2) and R3 MYB genes. GL2 is required for trichomeformation, whereas R3 MYBs inhibit trichome formation byblocking the formation of the MBW complex, thus inhibitingthe expression of GL2. By using the amino acid sequence of theArabidopsis R3 MYB transcription factor TRICHOMELESS1(TCL1) to BLAST the soybean (Glycine max) protein database,we found that there are a total of six R3 MYB genes insoybean, namely Glycine max TRICHOMELESS1 through 6(GmTCL1-GmTCL6). By generating transgenic plants, wefound that trichome formation in soybean plants overexpressingeach of the GmTCLs remained largely unchanged, and theexpression of putative GL1 and GL2 genes in the transgenicplants was unaffected. However, all the GmTCLs interactedwith GLABRA3 (GL3) in transfected Arabidopsis protoplasts,expression each of the GmTCLs in Arabidopsis inhibitedtrichome formation, and the expression levels of GL1 andGL2 were greatly reduced in the Arabidopsis transgenicplants. Moreover, phenotypic complementary analysis showedthat GmTCL1 is functionally equivalent to TCL1. Takentogether, these results suggest that GmTCLs are functionalR3 MYBs, however, they do not regulate trichome formationin soybean.

Test and Numerical Simulation of Partially Encased Composite Columns Subject to Axial and Cyclic Horizontal Loads

Yiyi Chen,Tuo Wang,Jing Yang,Xianzhong Zhao 한국강구조학회 2010 International Journal of Steel Structures Vol.10 No.4

Partial encased composite (PEC) members with thin steel plates and three types of constructional detailing are studied. Six pieces of PEC column specimens were tested under constant vertical load and cyclic horizontal loads. A numerical FE model is established. In the model, the in-filled concrete is decomposed as transverse and longitudinal springs, considering the functions and the properties of the concrete in two directions. This model simplifies the numerical computation with high efficiency, and acquires a satisfied agreement with test results in both capacity and deformability of the PEC member. The parametrical study by the FE model is performed. By tests and numerical analysis, it is found that though local buckling of thin plate of H steel is a crucial factor, when the compressively axial load does not surpass the encased steel capacity, the PEC could behave quite well under cyclic horizontal loads. No distinguished difference in three kind details was observed, so that PEC member could be built in a simple way.

Steel scale-CaO composite catalyst for coke combustion and in-situ NO and SO2 removal

Li Zhang,Jingchong Yan,Zhiping Lei,Xianzhong Cao,Tiejun Chun,Zhanku Li,Hengfu Shui,Shibiao Ren,Zhicai Wang,Ying Kong 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

The performance of the steel scale (SS)-CaO composite on the combustion of coke nuts and in-situ reductionof SO2 and NO emission was investigated. Combustion experiments show that SS-CaO compositeaccelerates coke combustion and reduces SO2 and NO emissions concurrently. X-ray diffraction (XRD),scanning electron microscopy (SEM), and electron spin resonance (ESR) were used to investigate thecatalysis mechanism. Results show that SS and CaO have synergistic effect in in-situ denitration. Theincrease of SS and CaO fraction in the composites improve the denitration and sulfur fixation performance,respectively. The denitration activity is mainly attributed to the Fe2O3 in SS and Ca2Fe2O5 formedduring combustion. The desulfurization is due to the sulfur fixation with CaO. The increasing fraction ofCaO in the composites leads to the agglomeration of ash particles. 2%CaO is confirmed as the optimumaddition for catalytic combustion and emission reduction. This work sheds light on the cheap and effectivecatalysts that are potentially useful for iron ore sintering.

Improved mechanical properties, barrier properties and degradation behavior of poly(butylenes adipate-co-terephthalate)/poly(propylene carbonate) films

Hongwei Pan,Yanping Hao,Yan Zhao,Xianzhong Lang,Ye Zhang,Zhe Wang,Huiliang Zhang,Lisong Dong 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.5

Poly(butylene adipate-co-terephthalate) (PBAT) was blended with poly(propylene carbonate) (PPC) by a twin screw extruder and then the blends were made onto films via the blown film technique. PPC dispersed uniformly in the PBAT matrix, and the glass transition temperature (Tg) of PBAT were decreased with the increasing content of PPC. Wide angle X-ray diffraction confirmed that the crystallite dimension of PBAT was decreased after blending PBAT with the amorphous PPC. The results of mechanical tests indicated that the PBAT/PPC films showed high tensile strength and tear strength. In addition, the PBAT/PPC films showed high carbon dioxide permeability and moderate oxygen and nitrogen permeability. After embedding in soil, the weight loss and mechanical properties analysis demonstrated that the films were remarkably biodegraded. These findings contributed to application of the biodegradable materials, such as design and manufacture polymer packaging.

The influence of surface lithium residue to the performance of LiNi0.9Co0.05Mn0.05O2 cathode materials

Liu Junjie,Chu Chenxiao,Qin Xianzhong,Meng Weisong,Xu Xinrui,Wang Bo,Cai Feipeng 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.3

High nickel ternary cathode materials (Ni ≥ 90%) have great potential for application as power batteries in electric vehicles and have become a hot spot for research on cathode materials. However, the residual Li on the surface of the high Ni ternary cathode materials prepared by solid-phase sintering is one of the main reasons affecting their electrochemical performance. It is found that Li1 + x(Ni0.9Co0.05Mn0.05)1-xO2 with x = 0.3, which has a discharge-specific capacity of 205.74 mAh g −1 at 2.7–4.3 V, 0.1C and 184.1 mAh g −1 at 1 C, retained 89% of its initial discharge capacity after 100 cycles at 1 C. The discharge-specifi c capacity at 10 C was 153.14 mAh g −1. In addition, the Li residue of NCM90-1.03 was 17,189.959 ppm, and the total alkalinity was 4196.896 ppm. The results by X-ray diff raction (XRD) and scanning electron microscope (SEM) showed that when the Li excess was 0.3%, it was possible to obtain uniform particle size, a wider Li layer, and reduced cation mixing. Therefore, choosing the right amount of excess Li can stimulate the application prospect of NCM90 in new energy vehicles.