Prediction of Shear-induced Crack Initiation in AHSS Deep Drawing Operation with a Phenomenological Fracture Model

Meng Luo,Yaning Li,Joerg Gerlach,Tomasz Wierzbicki 한국소성가공학회 2010 기타자료 Vol.2010 No.6

Advanced High Strength Steels (AHSS) draws enormous attentions in automotive industry because it has great potential in reducing weight and improving fuel efficiency. Nonetheless, their relatively low formability also causes many problems in manufacturing processes, such as shear-induced fracture during deep drawing or stamping. This type of fracture could not be predicted using traditional necking-based Forming Limit Diagram (FLD), which is commonly used by the forming community. In the present paper, a recently developed Modified Mohr-Coulomb (MMC)[1] ductile fracture model is employed to make up the deficiency of FLD. In the limiting case of plane stress, the MMC fracture locus consists of four branches when represented on the plane of the equivalent strain to fracture and the stress triaxiality. A transformation of above 2D fracture locus to the space of principal strains was performed which revealed the existence of two new branches not known before. The existence of those branches explains the formation of shear-induced fracture. As an illustration of this new approach, initiation and propagation of cracks in a series of deep drawing tests is predicted and compared with the experimental observations. It was shown that the location of fracture as well as the magnitude of punch travel corresponding to first fracture was correctly predicted by MMC fracture model for both square and circular punch cases.

Application of a Reduced Texture Methodology to Model the Plasticity of Anisotropic Extruded Aluminum Sheets

Meng Luo,Gilles Rousselier,Dirk Mohr 한국소성가공학회 2011 기타자료 Vol.2011 No.8

A recently developed Reduced Texture Methodology (RTM) featuring (ⅰ) a significantly reduced number of crystallographic orientations, (ⅱ) a special experiment-based parameter calibration procedure, and (ⅲ) reasonable computational time for industrial applications is adopted to model the anisotropic plastic behavior of a 2㎜-thick extruded aluminum 6260-T6 sheet. Firstly, the full-thickness sheet is modeled with twelve crystallographic orientations, and the model parameters are identified through an optimization procedure based on uniaxial tensile tests with seven different material orientations. The calibrated model describes well the stress-strain curves and Lankford ratios for all directions, while the optimized grain orientations are in good agreement with EBSD measurements. However, the EBSD results also reveal that the present sheet exhibits a strong heterogeneity through the thickness as far as crystallographic orientations and grain sizes are concerned. To account for this heterogeneity, eight grain orientations are selected out of the total twelve for the full-thickness sheet to model the 0.7㎜-thick central layer of the sheet based on the EBSD measurements. It is found that the reduced eight-grain model provides good predictions of the macroscopic responses in uniaxial tensile tests on reduced-thickness specimens, even without further calibration. A combined calibration is also performed to determine the final set of parameters which provide excellent modeling for both the full-thickness sheet (twelve-grain model) and its central layer (eight-grain model).

Numerical Analysis of AHSS Fracture in a Stretch-bending Test

Meng Luo,Xiaoming Chen,Ming F. Shi,Hua-Chu Shih 한국소성가공학회 2010 기타자료 Vol.2010 No.6

Advanced High Strength Steels (AHSS) are increasingly used in the automotive industry due to their superior strength and substantial weight reduction advantage. However, their limited ductility gives rise to numerous manufacturing issues. One of them is the so-called ‘shear fracture’ often observed on tight radii during stamping processes. Since traditional approaches, such as the Forming Limit Diagram (FLD), are unable to predict this type of fracture, efforts have been made to develop failure criteria that can predict shear fractures. In this paper, a recently developed Modified Mohr-Coulomb (MMC) ductile fracture criterion[1] is adopted to analyze the failure behavior of a Dual Phase (DP) steel sheet during stretch bending operations. The plasticity and ductile fracture of the present sheet are fully characterized by the Hill’48 orthotropic model and the MMC fracture model respectively. Finite Element models with three different element types (3D, shell and plane strain) were built for a Stretch Forming Simulator (SFS) test and numerical simulations with four different R/t ratios (die radius normalized by sheet thickness) were performed. It has been shown that the 3D and shell element models can accurately predict the failure location/mode, the upper die loaddisplacement responses as well as the wall stress and wrap angle at the onset of fracture for all R/t ratios. Furthermore, a series of parametric studies were conducted on the 3D element model, and the effects of tension level (clamping distance) and tooling friction on the failure modes/locations were investigated.

LncRNA TMPO-AS1 promotes esophageal squamous cell carcinoma progression by forming biomolecular condensates with FUS and p300 to regulate TMPO transcription

Luo Xiao-Jing,He Ming-Ming,Liu Jia,Zheng Jia-Bo,Wu Qi-Nian,Chen Yan-Xing,Meng Qi,Luo Kong-Jia,Chen Dong-Liang,Xu Rui-Hua,Zeng Zhao-Lei,Liu Ze-Xian,Luo Hui-Yan 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Esophageal squamous cell carcinoma (ESCC) is one of the most life- and health-threatening malignant diseases worldwide, especially in China. Long noncoding RNAs (lncRNAs) have emerged as important regulators of tumorigenesis and tumor progression. However, the roles and mechanisms of lncRNAs in ESCC require further exploration. Here, in combination with a small interfering RNA (siRNA) library targeting specific lncRNAs, we performed MTS and Transwell assays to screen functional lncRNAs that were overexpressed in ESCC. TMPO-AS1 expression was significantly upregulated in ESCC tumor samples, with higher TMPOAS1 expression positively correlated with shorter overall survival times. In vitro and in vivo functional experiments revealed that TMPO-AS1 promotes the proliferation and metastasis of ESCC cells. Mechanistically, TMPO-AS1 bound to fused in sarcoma (FUS) and recruited p300 to the TMPO promoter, forming biomolecular condensates in situ to activate TMPO transcription in cis by increasing the acetylation of histone H3 lysine 27 (H3K27ac). Targeting TMPO-AS1 led to impaired ESCC tumor growth in a patient-derived xenograft (PDX) model. We found that TMPO-AS1 is required for cell proliferation and metastasis in ESCC by promoting the expression of TMPO, and both TMPO-AS1 and TMPO might be potential biomarkers and therapeutic targets in ESCC.

Z-scheme Bi2O3/Bi/ZnIn2S4 photocatalyst for enhancing the removal performance of Cr(VI), 2,4-dinitrophenol and tetracycline

Jing Luo,Zhaoxia Shi,Jiefeng Meng,Feng Li,Taohai Li,Meng Zhang,Rossella Greco,Wei Cao 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-

Construction of heterojunctions is conventionally regarded as the prevailing technique to enhance solardrivenphotocatalytic water splitting and photodegradation of pollutants. Herein, we report a noveldesign of a ternary Bi2O3/Bi/ZnIn2S4 system, which was facilely synthesized to satisfy these stringent criteriafor sunlight photocatalytic removal of organic and ionic pollutants and hydrogen evolution. Bi2O3/Bi/ZnIn2S4 could degrade 2,4-dinitrophenol (94.6%), tetracycline (96.5%), and Cr6+ (96.3%) effectivelyunder visible light and give a hydrogen production rate of 482.5 lmolg1h1 under visible light. Based on first-principles calculations and electrochemical results, our system could be identified as aZ-scheme. Photocorrosion of the sulfide is prohibited while the catalytic capabilities are simultaneouslybenefited due to lowered bandgap in light harvesting, internal electric fields in charge separations, andsurface plasmonic resonance enhanced electron boost.

Design of Dynamic Calf Weighing System Based on Moving-IIR Filter Algorithm

Meng Hewei,Luo Jinjun,Li Shenglin,Qi Jiangtao,Wenwen Zhao,Li Yaping 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.2

In order to solve the problems of high intensity, low collecting effi ciency, poor information real-time performance and low precision in the calf weighing process, a kind of dynamic calf weighing system was designed. It was based on moving-IIR by establishing a test platform to verify fi lter algorithm. The software MATLAB was applied to design the moving average fi lter algorithm, IIR fi lter algorithm and moving-IIR fi lter algorithm, respectively, to process and analyze the dynamic data collected in slow, violent and slow-violent states of calves. Test results showed that, the error rates of moving-IIR fi lter algorithm in slow, violent and slow-violent states of calves were within 1.12%, 0.32% and 2.82%, which were lower than that of moving-average fi lter algorithm and IIR fi lter algorithm. In slow state of calves, the moving-IIR fi lter was not very smooth. In violent and slow-violent states of calves, the standard deviations were within 1.1126 and 1.1520, showing signifi cant smoothness. The study showed that, information collection system based on moving-IIR fi lter algorithm has fully taken the stability of moving fi lter and dynamic nature of IIR fi lter into consideration and had advantages of low error rate and high stability. Therefore, it can realize real time precise collection, display, storage and historical data query of weight information.

Vacuum Carbonization of Nanometer Tungsten Powder with Carbon Black

Luo Ji,Lin Tao,Guo Zhi-meng,Jia Chengchang 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Vacuum carbonization of nanometer tungsten powder was investigated in a simple designed apparatus. An X-Y recorder was used to plot differential thermal analysis (DTA) curves to determine starting temperature of carbonization of four samples with different specific surface area. The product was detected by X-ray Diffraction (XRD) and small angle X-ray scattering (SAXS). The results show that finer tungsten powder has lower starting temperature of carbonization. Tungsten powder, which BET surface area is , is completely carbonized to tungsten carbide at , although the starting temperature is . Particle grows sharply before carbonization.

Dynamic analysis of viscoelastic concrete plates containing nanoparticle subjected to low velocity impact load

Luo, Jijun,Lv, Meng,Hou, Suxia,Nasihatgozar, Mohsen,Behshad, Amir Techno-Press 2022 Advances in nano research Vol.13 No.4

Dynamic study of concrete plates under impact load is presented in this article. The main objective of this work is presenting a mathematical model for the concrete plates under the impact load. The concrete plate is reinforced by carbon nanoparticles which the effective material proprieties are obtained by mixture's rule. Impacts are assumed to occur normally over the top layer of the plate and the interaction between the impactor and the structure is simulated using a new equivalent three-degree-of-freedom (TDOF) spring-mass-damper (SMD) model. The structure is assumed viscoelastic based on Kelvin-Voigt model. Based on the classical plate theory (CPT), energy method and Hamilton's principle, the motion equations are derived. Applying DQM, the dynamic deflection and contact force of the structure are calculated numerically so that the effects of mass, velocity and height of the impactor, volume percent of nanoparticles, structural damping and geometrical parameters of structure are shown on the dynamic deflection and contact force. Results show that considering structural damping leads to lower dynamic deflection and contact force. In addition, increasing the volume percent of nanoparticles yields to decreases in the deflection.

Convergence analysis of a family of 14-node brick elements

Meng, Zhaoliang,Luo, Zhongxuan,Sheen, Dongwoo,Kim, Sihwan Elsevier 2016 Journal of computational and applied mathematics Vol.301 No.-

<P><B>Abstract</B></P> <P>In this paper, we will give convergence analysis for a family of 14-node elements which was proposed by Smith and Kidger (1992). The 14 DOFs are taken as the values at the eight vertices and the six face-centroids. For second-order elliptic problems, we will show that among all the Smith–Kidger 14-node elements, Type 1, Type 2 and Type 5 elements provide optimal-order convergent solutions while Type 6 element gives one-order lower convergent solutions. Motivated by our proof, we also find that the order of convergence of the Type 6 14-node nonconforming element improves to be optimal if we change the DOFs into the values at the eight vertices and the integration values on the six faces. We also show that Type 1, Type 2 and Type 5 keep the optimal-order convergence if the integral DOFs on the six faces are adopted.</P>

Myeloid-Derived Suppressor Cells Recruited by Chemokine (C-C Motif) Ligand 3 Promote the Progression of Breast Cancer via Phosphoinositide 3-Kinase-Protein Kinase B-Mammalian Target of Rapamycin Signaling

Anqi Luo,Min Meng,Guanying Wang,Rui Han,Yujiao Zhang,Xin Jing,Lin Zhao,Shanzhi Gu,Xinhan Zhao 한국유방암학회 2020 Journal of breast cancer Vol.23 No.2

Purpose: Numerous studies have shown that the frequency of myeloid-derived suppressor cells (MDSCs) is associated with tumor progression, metastasis, and recurrence. Chemokine (C-C motif ) ligand 3 (CCL3) may be secreted by tumor cells and attract MDSCs into the tumor microenvironment. In the present study, we aimed to explore the molecular mechanisms whereby CCL3 is involved in the interaction of breast cancer cells and MDSCs. Methods: The expression of CCL3 and its receptors was investigated using real-time polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. The cell counting Kit-8, wound healing, and transwell assays were performed to study cell growth, migration, and invasion. Cell cycling, apoptosis, and the frequency of MDSCs were investigated through flow cytometry. Transwell assays were used for co-culture and chemotaxis detection. Markers of the epithelial-mesenchymal transition (EMT) were determined with western blotting. The role of CCL3 in vivo was studied via tumor xenograft experiments. Results: CCL3 promoted cell proliferation, migration, invasion, and cycling, and inhibited apoptosis of breast cancer cells in vitro. Blocking CCL3 in vivo inhibited tumor growth and metastases. The frequency of MDSCs in patients with breast cancer was higher than that in healthy donors. Additionally, MDSCs might be recruited by CCL3. Co-culture with MDSCs activated the phosphoinositide 3-kinase-protein kinase B-mammalian target of rapamycin (PI3K-Akt-mTOR) pathway and promoted the EMT in breast cancer cells, and their proliferation, migration, and invasion significantly increased. These changes were not observed when breast cancer cells with CCL3 knockdown were co-cultured with MDSCs. Conclusion: CCL3 promoted the growth of breast cancer cells, and MDSCs recruited by CCL3 interacted with these cells and then activated the PI3K-Akt-mTOR pathway, which led to EMT and promoted the migration and invasion of the cells.