Optimization of the construction scheme of the cable-strut tensile structure based on error sensitivity analysis

Lian-meng Chen,Dong Hu,Hua Deng,Yu-hong Cui,Yi-yi Zhou 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.5

Optimization of the construction scheme of the cable-strut tensile structure based on error sensitivity analysis is studied in this paper. First, the element length was extracted as a fundamental variable, and the relationship between element length change and element internal force was established. By setting all pre-stresses in active cables to zero, the equation between the pre-stress deviation in the passive cables and the element length error was obtained to analyze and evaluate the error effects under different construction schemes. Afterwards, based on the probability statistics theory, the mathematical model of element length error is set up. The statistical features of the pre-stress deviation were achieved. Finally, a cable-strut tensile structure model with a diameter of 5.0 m was fabricated. The element length errors are simulated by adjusting the element length, and each member in one symmetrical unit was elongated by 3 mm to explore the error sensitivity of each type of element. The numerical analysis of error sensitivity was also carried out by the FEA model in ANSYS software, where the element length change was simulated by implementing appropriate temperature changes. The theoretical analysis and experimental results both indicated that different elements had different error sensitivities. Likewise, different construction schemes had different construction precisions, and the optimal construction scheme should be chosen for the real construction projects to achieve lower error effects, lower cost and greater convenience.

Identification and Adjustment of the Pretension Deviation in Cable-Strut Tensile Structures

Lian-meng Chen,Zhichao Jiang,Wei-feng Gao,Yi-yi Zhou 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.1

Construction errors inevitably arise in real cable-strut tensile structures. Nevertheless, construction error analysis and evaluation, as well as methods to identify the source of the errors and proper adjustment methods to compensate for these errors, remain in their infancies. In this study, the relationship between pretension deviation and element length deviation is first established based on the three basic equations for pin-joint structures. On this basis, identification methods are proposed to identify the sources of the pretension deviation caused by the active cable length deviation and the pretension deviation caused by both the active and the passive cable length deviations. Using measured data, an adjustment method is developed for the pretension deviation under different scenarios. Furthermore, the effectiveness of the adjustment method for the pretension deviation is discussed using the evaluation indices. Finally, a case study is presented and demonstrates that the proposed identification method can identify the sources of the pretension deviations. The number of adjusted cables will affect the level of adjustment for the pretension deviation. During the adjustment of the pretension deviation, different adjustment methods will result in different shape deviations and different maximum displacements.

Robustness Analysis of a Flexible Cable-Strut Tensile Structure

Lian-meng Chen,Wei-feng Gao,Zhichao Jiang,Yi-yi Zhou,Fu-bo Zhang,Shi-lin Dong 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.5

Currently, the robustness analysis of structure is primarily related to rigid structures, and little has been done to study the robustness of spatial fl exible cable-strut tensile structures with larger span, more complex forms, lower redundancy, more sensitivity to unexpected interference such as construction deviations, etc. Based on the H ∞ theory, this paper starts with the fundamental theory and develops analysis method for the robustness of fl exible cable-strut tensile structures, and then the relationships between the structural robustness and some design parameters such as initial pre-stress level, load distribution form, structural span, cross-section area, rise-span ratio, etc. are analysed through a case study of a concrete cable-strut tensile structure in China. On this basis, the eff ects of construction errors such as element-length error and supporting node position error are further analysed. Finally, the importance of each kind of element is analysed by means of conceptual removal of element. The results show that the higher the initial pre-stress level, the larger the element cross-section, the smaller the structural span, the larger the rise-span ratio and the more uniform the load distribution, the stronger the structural robustness. In the limited construction error range, the element-length error and the supporting node position error have little eff ects on the robustness of the structure. The hoop cables are the more important elements and the elements in inner region of the structure are of comparatively lower importance in the cable dome structure in this study.

Determination of a Monitoring Scheme for Controlling Construction Errors of a Cable-strut Tensile Structure

Lian-meng Chen,Wei-feng Gao,Dong Hu,Yi-yi Zhou,Fu-bo Zhang,Shi-lin Dong 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

Construction errors are inevitable in real cable-strut tensile structures. Nevertheless, the relevant work, especially the monitoring scheme design work, to control the construction errors is lacking. At present, the monitoring schemes always lay out the monitored members in the places with great internal force or great deformation, do not consider the method to control the construction errors and do not explain the method to lay out the monitored members in fundamental theory. To address this situation, the element length error, which is an important construction error affecting the bearing performance, is considered as the factor variable and the fundamental equation of pre-stress deviation and element length error is derived firstly. Next the methods to express the pre-stress deviation, which are only derived from the active cable length errors or from both the active cable and passive cable length errors, are discussed. After that, based on the condition that the errors can be solved and compensated, the least number of monitored members is determined. Moreover, those members sensitive to cable length deviation of active cables are selected as monitored members. In order to evaluate the effect level caused by passive cable length deviation, two evaluation parameters Δ and ρ are further discussed. Finally, one cable-strut tensile structure example is employed to verify the proposed method and the results of the example studies indicate that the least necessary number of monitored members can be achieved for the accurate solution and compensation of active cable length deviations. Different members have different sensitivities to the change of the length in active cables and those members with great sensitivities can be chosen in prior as monitored members. The evaluation parameters Δ and ρ can be used to analyze the source of errors and to evaluate the error effect level caused by the passive cable length deviation.

Low cycle fatigue properties of hydrogenated welding sheets of Zr–Sn–Nb alloy using funnel-shaped flat specimens

Lian-feng Wei,Chen Bao,Shi-zhong Wang,Yong Zheng,Meng-bin Zhou 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.8

Low cycle fatigue tests on the hydrogenated welding seam of ZreSneNb alloy at room temperature and 360 C had been carried out by using the funnel-shaped flat specimens. The relationships between nominal stress & strain directly measured across the funnel and local stress & strain at the root of the funnel are given by considering cyclic plasticity correction. The results show that the fatigue resistance of welding seam at room temperature is only slightly better than that at 360 C. Probabilistic fatigue life curves are obtained by using a two-parameter power function.

Study of the Enhancement of Magnetic Properties of NdFeB Materials Fabricated by Modified HDDR Process

Meng Fu,Fa-zeng Lian,Ji-jie Wang,Wen-li Pei,Yu-lan Chen,Hong-cai Yang 한국자기학회 2004 Journal of Magnetics Vol.9 No.4

The HDDR (Hydrogenation-Disproportionation-Desorption-Recombination) process is a special method to produce anisotropic NdFeB powders for bonded magnet. The effect of the modified HDDR process on magnetic properties of Nd₂Fe₁₄B-based magnet with several composition Nd_(11.2)Fe_(66.5-x)Co_(15.4)B_(6.8)Zr_(0.1)Ga_x (x = 0~1.0) and that of microelement Ga, disproportional temperature and annealing temperature on jHc, grain size were investigated in order to produce anisotropic powder with high magnetic properties. It was found that modified HDDR process is very effective to enhance magnetic properties and to fine grain size. The addition of Ga could change disproportionation character remarkably of the alloy and could improve magnetic properties of magnet powder. Increasing annealing temperature induces significant grain growth. And grain size produced by modified HDDR process is significantly smaller than those produced by conventional HDDR process.

Increased retinoic acid signaling decreases lung metastasis in salivary adenoid cystic carcinoma by inhibiting the noncanonical Notch1 pathway

Zhou Meng-jiao,Yang Jia-jie,Ma Ting-yao,Feng Ge-xuan,Wang Xue-lian,Wang Li-Yong,Ge Yu-ze,Gao Ran,Hong-liang Liu,Shan Lin,Kong Lu,Chen Xiao-hong 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

MYB-NFIB fusion and NOTCH1 mutation are common hallmark genetic events in salivary gland adenoid cystic carcinoma (SACC). However, abnormal expression of MYB and NOTCH1 is also observed in patients without MYB-NFIB fusion and NOTCH1 mutation. Here, we explore in-depth the molecular mechanisms of lung metastasis through single-cell RNA sequencing (scRNA-seq) and exome target capture sequencing in two SACC patients without MYB-NFIB fusion and NOTCH1 mutation. Twenty-five types of cells in primary and metastatic tissues were identified via Seurat clustering and categorized into four main stages ranging from near-normal to cancer-based on the abundance of each cell cluster in normal tissue. In this context, we identified the Notch signaling pathway enrichment in almost all cancer cells; RNA velocity, trajectory, and sub-clustering analyses were performed to deeply investigate cancer progenitor-like cell clusters in primary tumor-associated lung metastases, and signature genes of progenitor-like cells were enriched in the “MYC_TARGETS_V2” gene set. In vitro, we detected the NICD1-MYB-MYC complex by co-immunoprecipitation (Co-IP) and incidentally identified retinoic acid (RA) as an endogenous antagonist of genes in the “MYC_TARGETS_V2” gene set. Following this, we confirmed that all-trans retinoic acid (ATRA) suppresses the lung metastasis of SACC by correcting erroneous cell differentiation mainly caused by aberrant NOTCH1 or MYB expression. Bioinformatic, RNA-seq, and immunohistochemical (IHC) analyses of primary tissues and metastatic lung tissues from patients with SACC suggested that RA system insufficiency partially promotes lung metastasis. These findings imply the value of the RA system in diagnosis and treatment.

The microstructure evolution and mechanical properties of ammonium polyphosphate/ aluminium hydroxide/ mica during thermal reaction

Sheng HU,Fei Chen,Jun-Guo Li,Qiang Shen,Zhi-Xiong Huang,Lian-Meng Zhang 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.8

The phase and microstructure evolution of ammonium polyphosphate/ aluminium hydroxide/ mica compounds (AAM) duringthermal reaction are investigated. At 300 oC, AAM residues exhibit porous structure due to gas evolution from the thermaldecomposition of ammonium polyphosphate (APP) and aluminium hydroxide, but mica does not react with them, and theflexural strength of specimens can reach 11.56 MPa. The thermal decomposition products of APP react with AlOOH toNH4AlP2O7, which can improve the flexural strength during 300 ~ 400 oC. The reactivity of mica is increased by eliminatinghydroxyl at temperature up to 600 oC, and the flexural strength of AAM residues is improved furtherly by the chemicallyinteractions between active mica and phosphates during 600 ~ 1000 oC. And specifically at 1000 oC, the AAM residues exhibitrelatively high flexural strength, which can reach 26.85 MPa and reactions between mica and KAlP2O7 could generateKAlSi3O8 and 3Al2O3·2SiO2. AAM with high flexural strength from low to high temperatures is expected to be a kind ofexcellent inorganic additive of ceramifiable polymer with wide temperature range for using.

The Gender-Sensitive Social Risk Factors for Internet Addiction in College Undergraduate Students

Xia Lin,Jing-yan Gu,Wan-jun Guo,Ya-jing Meng,Hui-yao Wang,Xiao-jing Li,Wei Deng,Lian-sheng Zhao,Xiao-hong Ma,Ming-li Li,Ting Chen,S,K,Cheng,Tao Li 대한신경정신의학회 2021 PSYCHIATRY INVESTIGATION Vol.18 No.7

Objective The current study aims to explore precipitating and social risk factors for internet addiction (IA) in university undergraduate students, and to provide evidence for interventions and the early prevention of IA in different genders. Methods Four thousand eight hundred and fifty-eight college sophomores completed an online survey on their internet use-related behaviours and social risk factors. Results We found that more male (8.3%) than female students (5.4%) had moderate and severe IA. The main online activity in the moderate and severe IA groups was online gaming in males and online streaming in females. Roommates engaging in similar internetbased entertainment was a risk factor of IA only for males, while not being in a romantic relationship was a risk factor of IA for females only. Infatuation with the internet before college and adjustment problems for college life were shared risk factors for both genders in the mild and moderate IA groups. Conclusion IA was a common phenomenon in college students with shared and unique precipitating and social risk factors in males and females. The gender-sensitive risk factors for IA warranted earlier and individualized intervention and prevention strategies for IA in this population.