Finite element study on shear performances of in-filled bolt joint of assembled grc wall with light steel skeleton frame

A new in-filled wall is used in assembled steel structure buildings, which consists of two layers of glass fiber reinforced concrete (GRC) panels and a built-in light steel skeleton frame. To make this new wall fill in the main steel structure, a new in-filled bolt joint is used. In order to obtain the mechanical properties and failure modes under shear load, the shear performances of this joint were studied with the finite element (FE) software ABAQUS. The results show that before reaching the fracture failure strain, the in-filled bolt joint shows good elastic-plastic behaviour. When the strain of the in-filled bolt joint reaches the failure strain, the shear load reaches the peak value. Subsequently, due to the shear fracture of the bolt, the shear load drops rapidly. Throughout the loading process, the stress of steel beam and rectangular steel tube is always very small and the stress of the joint yields in a large area in the later stage

Finite element study on mechanical performances of multi-span metal faced sandwich panels under temperature actions

Metal faced sandwich panel is composed of two relatively high strength metal faces and a relatively thick and lightweight insulated core. Under the continuous action of temperature such as strong sunlight, the multi-span metal faced sandwich panels can be destroyed. In this paper, the finite element (FE) software ABAQUS was used to study the stress and deformation of these sandwich panels under temperature action. The FE results show that the compressive stress in the mid-span region of the metal panel is larger and it gradually decreased from the middle to the two sides. The deformation at the centre of side span of sandwich panels is larger. The support constraints at the bottom of the sandwich panel have a great influence on the temperature stress. The fixed sandwich panel is more likely to occur wrinkle failure than the hinged one. To reduce the effects of temperature, two effective methods are proposed. The method increasing the density of the core material can increase the buckling stress and improve the bearing capacity against temperature action. The other method reducing the length of each segment of the sandwich panel can effectively release the temperature stress and reduce the negative effects of temperature

Finite element study on bearing capacities of hook-bolt joint of assembled GRC wall with light steel skeleton frame

A new assembled external wall is composed of two glass fiber reinforced concrete (GRC) panels and built-in light steel skeleton frames and a layer of filled insulated core materials. To connect this new wall to the main steel structure, the new hook-bolt joint is used. The finite element (FE) software ABAQUS was used to study the bearing capacities of hook-bolt joint under horizontal force and vertical force. The FE results show that under horizontal and vertical force, the hook-bolt joint shows good elastic-plastic behaviour. In the initial stage of displacement loading, there is slip displacement stage and the load is very small. After this initial stage, with the gradual increase of displacement, the load increases gradually. Larger stresses are mainly distributed at the intersection of the hook-shaped connector and the U-shaped connector. The vertical bearing capacity of the hook-bolt joint is about two times larger than that of horizontal one. These studies can provide referential basis for the design and application of the hook-bolt joint of the assembled wall with light steel skeleton frame

Effects of tension-compression asymmetry on bending of steels

Stainless steels (SUS) and dual-phase (DP) steels have tension-compression asymmetry (TCA) in mechanical responses to full loading cycles. This phenomenon can significantly influence sheet metal forming of such metals, however, it is difficult to describe this behaviour analytically. In this research, a novel analytical method for asymmetric elastic-plastic pure bending using the Cazacu–Barlat 2004 asymmetric yield function is proposed. It only uses material parameters in tension along with an asymmetry coefficient related to the yield function. Bending operations of SUS304 and DP980 are investigated as two case studies. In the pure bending for both SUS304 and DP980, moment–curvature diagrams are analytically obtained. Furthermore, linear and nonlinear springback behaviours of SUS304 are analytically investigated. Moreover, using the analytical model as a user-defined material, a numerical model is developed for both steels under pure bending. In the V-bending case of SUS304 with and without TCA effects, the springback behaviours of the material are investigated numerically. In addition, considering friction effects, the analytical method is further modified for predicting springback behaviours in the V-bending of 16 types of SUS304 with various strengths are determined. All the analytical and numerical results have good agreement with those experimental results from literature for validation

First-principles studies on the structural and electronic properties of as clusters

Based on the genetic algorithm (GA) incorporated with density functional theory (DFT) calculations, the structural and electronic properties of neutral and charged arsenic clusters Asn (n = 2-24) are investigated. The size-dependent physical properties of neutral clusters, such as the binding energy, HOMO-LUMO gap, and second difference of cluster energies, are discussed. The supercluster structures based on the As8 unit and As2 bridge are found to be dominant for the larger cluster Asn (n ≥ 8). Furthermore, the possible geometric structures of As28, As38, and As180 are predicted based on the growth pattern

Wear characteristics of cutting tool in brittle removal of a ductile meta in high-speed machining

The contact stress and heating effect between the cutting tool and workpiece in metal machining is symmetrical. However, the symmetry may be destroyed by changes in the workpiece material mechanical properties, such as ductility. The goal of this study is to reveal the wear characteristics of the cutting tool in machining a ductile metal with the cutting speed at which the metal is embrittled by the high-strain-rate-embrittle effect (HSREE). Orthogonal high-speed turning experiments were carried out. Pure iron type DT8 was cut at different cutting speeds, ranging from 1000 m/min to 9000 m/min. The shape and morphology of the chips obtained in the experiment were observed and analyzed by optical microscope and scanning electron microscope (SEM). Tool wear characteristics at different cutting speeds were observed. It shows that the pure iron becomes completely brittle when the cutting speed is higher than 8000 m/min. On the rake face, the coating of the cutting tool bursts apart and peels off. A matrix crack originates in the cutting edge or rake face and extends to the flank face of the cutting tool. The effects of HSREE on the tool wear is discussed. The findings of this study are helpful for choosing a suitable tool for brittle cutting of the ductile metal pure iron with very high cutting speed and solving the problems in machining due to its high ductility and high stickiness

Numerical modelling of additive manufacturing process for stainless steel tension testing samples

Nowadays additive manufacturing (AM) technologies including 3D printing grow rapidly and they are expected to replace conventional subtractive manufacturing technologies to some extents. During a selective laser melting (SLM) process as one of popular AM technologies for metals, large amount of heats is required to melt metal powders, and this leads to distortions and/or shrinkages of additively manufactured parts. It is useful to predict the 3D printed parts to control unwanted distortions and shrinkages before their 3D printing. This study develops a two-phase numerical modelling and simulation process of AM process for 17-4PH stainless steel and it considers the importance of post-processing and the need for calibration to achieve a high-quality printing at the end. By using this proposed AM modelling and simulation process, optimal process parameters, material properties, and topology can be obtained to ensure a part 3D printed successfully

Association of MUC1 rs4072037 functional polymorphism and cancer risk : Evidence from 12551 cases and 13436 controls

Objectives: The result of the relationship between the MUC1 rs4072037 polymorphism and cancer risk is controversial, we take this meta-analysis to investigate a more precise result. Methods: Electronic database Pubmed, Web of science and Cochrane library had been used to search relevant articles concerning the relationship between MUC1 rs4072037 polymorphism and cancer risk. We used odds ratios (ORs) and 95% confidence intervals (CIs) to assess the strength of the gene-disease association. We also conducted subgroup analysis, sensitivity analyses and publication bias in the meta-analysis. Results: In our meta-analysis, we involved 17 studies (19 datasets) with 12551 cases and 13436 controls eventually. It showed the MUC1 rs4072037 polymorphism was associated with decreased cancer risk in four genetic models (G vs. A: OR=0.79, 95%CI: 0.71-0.89, P < 0.001; AG vs. AA: OR=0.72, 95%CI: 0.62-0.82, P < 0.001; GG vs. AA: OR=0.78, 95%CI: 0.69-0.88, P < 0.001; AG+GG vs. AA: OR=0.72, 95%CI: 0.63-0.83, P < 0.001). In subgroup analysis, it showed a decreased cancer risk among Asians but not Caucasians and a significant decreased gastric cancer risk in all genetic models. Conclusion: MUC1 rs4072037 polymorphism is associated with decreased cancer risk and can probably be used as a tumor marker, especially for gastric cancer and for Asians

Prognostic role of MicroRNA-497 in cancer patients : A meta-analysis

Background: MicroRNA-497(miR-497) has been studied for its irreplaceable role of predicting the prognosis of various cancers, but there has been no systematic study to summarize the data. Consequently, we performed this meta-analysis to reveal the association between the expression level of miR-497 and cancer prognosis systematically. Materials and Methods: PubMed was searched for appropriate studies and a total of 12 eligible publications with 989 cancer patients were recruited into our analysis to assess the strength of the association. Hazard ratios (HRs) and odds ratios (ORs) were analyzed to finish this work. Results: The cancer patients who have high expressing level of miR-497 are less possible to have lymph node metastasis (OR = 0.25, 95% CI: 0.16-0.40, P < 0.001) and more likely to have favourable tumor-node-metastasis stage (OR = 0.29, 95% CI: 0.17-0.49, P < 0.001). Also, high miR-497 expression level was notably connected to better overall survival (pooled HR = 0.41, 95% CI: 0.32-0.53, P < 0.001). Conclusions: High expressing levels of miR-497 might be a potential biomarker which can be used to predict the better prognosis of different cancer types

RCN1 induces sorafenib resistance and malignancy in hepatocellular carcinoma by activating c-MYC signaling via the IRE1α–XBP1s pathway

The increasing incidence of hepatocellular carcinoma (HCC) is of great concern globally, but the molecular pathogenesis of these tumors remains unclear. Sorafenib is a first-line drug for the treatment of advanced HCC. However, the efficacy of sorafenib in improving patient survival is limited, and most patients inevitably develop resistance to this drug. Recent studies have demonstrated that the activation of the IRE1α–XBP1s pathway might play a protective role in the response to sorafenib and contribute to malignancy in HCC. Here, we found that RCN1, an endoplasmic reticulum resident protein, is significantly upregulated in sorafenib-resistant HCC cells and promotes tumor progression. Our analysis showed that RCN1 may be an independent predictor of tumor recurrence and overall survival. Mechanistically, RCN1 promotes the dissociation of GRP78 from IRE1α in sorafenib-resistant cells by interacting with GRP78 through its EFh1/2 domain. Subsequently, the IRE1α–XBP1s pathway, a branch of the unfolded protein response, is sustainably activated. Interestingly, IRE1α–XBP1s pathway activity is required for c-MYC signaling, one of the most highly activated oncogenic pathways in HCC. These results suggest that RCN1-targeted therapy might be a feasible strategy for the treatment of HCC