Stress Of Blank Research Articles

ЧИСЛЕННОЕ МОДЕЛИРОВАНИЕ ДЕФОРМАЦИЙ В АДДИТИВНОМ ТЕХНОЛОГИЧЕСКОМ ПРОЦЕССЕ ЛАЗЕРНОЙ ПОРОШКОВОЙ НАПЛАВКИ

This article discusses the modeling of the stress-strain state of products during laser powder surfacing using the example of a stepped tubular sample. To calibrate the model, a number of experiments were carried out using an additive powder with a fractional composition of 40–80 μm. During laser powder surfacing of samples, two-point thermometry was carried out, which is necessary for the subsequent calibration of the temperature problem. Powder surfacing was carried out in one layer with pauses between the deposited paths according to the surfacing modes. Helium and argon were used as shielding gases. The creation of an applied tool for the preliminary numerical assessment of warpage and residual stresses in blanks and DSE before carrying out repair technological operations using the powder laser cladding method, which allows for prompt approximate calculations, was the main task of the work. In the model, the element birth/death method was considered, which makes it possible to implement the appearance of hardfacing bodies and is the most convenient in this case. Warping modeling was carried out by dividing the welded part into tracks, which, in turn, are divided into hardfacing bodies. The next stage is the heatingand cooling of each elementary body along the surfacing trajectory, instead of modeling a moving heat source. Command inserts allow you to adjust the surfacing trajectory using automatic numbering of elementary bodies. The proposed technique makes it possible to quickly preprocess the problem and obtain sufficiently accurate calculation results in a short time. The results of modeling and real laser powder surfacing were compared. Verification of the developed model was carried out using the digitized outer surface of the existing experimental samples after surfacing. Calculations show sufficient computational accuracy of the model, however, the use of high-temperature properties of the powder material will reduce the calculation error.

Xiaoyaosan, a traditional Chinese medicine, inhibits the chronic restraint stress-induced liver metastasis of colon cancer in vivo

Context Xiaoyaosan (XYS), a traditional Chinese medicine (TCM), has been widely used to relieve a variety of disorders caused by depression. Objective This study evaluates the effect of XYS against tumour metastasis in a chronic restraint stress mouse model. Methods and materials Forty C57BL/6J mice were randomly divided into four groups, including blank-control (BC), blank-stress (BS), XYS-control (XC) and XYS-stress (XS). BS and XS groups were exposed to immobilization stress for 2 h per day for 28 days commencing seven days before tumour cell injection. XC and XS groups were given a gavage of XYS (1516.67 mg/kg) before chronic immobilization stress. Mice were injected with HT-29 colon cancer cells in the spleen to produce liver metastasis. After 28 days of injecting with HT-29 cells, flow cytometry, western blot, PCR and immunohistochemical staining were performed to uncover the role of chronic restraint stress and XYS in the liver metastasis of colon cancer. Results Metastatic liver weight of mice in XS group (3.33 ± 0.18 g) was significantly lower than BS group (4.01 ± 0.27 g). Chronic restraint stress significantly increased CD11b+F4/80+ and CD11b+GrloLy6Chi cell infiltration. XYS treatment significantly decreased the CD11b+F4/80+ tumour-associated macrophage (TAM) population and CD11b+GrloLy6Chi myeloid-derived suppressor cell (MDSC). TGF-β, IL-6, MMP-9 and VEGF in spleen tumours significantly decreased in XYS group. XYS also reduced VEGF and CD31 in hepatic metastatic tissue, which were elevated by chronic restraint stress. Conclusions XYS may successfully inhibit chronic-stress-induced liver metastasis. Results suggest that XYS may have therapeutic value for colorectal cancer treatment.

Macro-Residual Stress Field Retrieval for Predicting the Machining Deformation of Non-Prestretched Plate

The unknown and uneven macro-residual stresses in blanks will cause deformation on large-scale component, especially in non-prestretched plates. Based on the retrieval of stress field by measuring stress changes due to the rebalance of stresses after machining, a new idea is proposed in this paper to predict and control the machining deformation of large-scale components. It consists of analysis of the machining deformation, retrieval of macro-residual stress field, and finally optimization of following cutting process. In the retrieval process, the stresses are measured with an improved hole-drilling method and the measured data are then interpolated to 3D stress field.