Study of mechanical behavior by fatigue of a cracked plate repaired by different composite patches

This research is based on the study of the fatigue behavior of an aluminum alloy plate with a central crack. The plate is subjected to a tensile loading on its lower and upper parts. Several parameters were highlighted, such as the loading effect with a load ratio R = 0. The effects of the load ratio on both the repaired and not repaired plates, by two composite patches, which are boron/epoxy and graphite/epoxy, were investigated, as well as the effect of the plate material on plate life, comparing different material

Comparative study of the repair of cracked plates with two different composite patches

The purpose of this study is to analyze the behavior of a crack with and without reinforcement by a composite patch of an aluminum plate in mode I using the finite element method. The repair patch is boron / epoxy and Carbon / epoxy, which are used with great success by many researchers For the distribution of the stresses according to the various loadings, we can conclude that the effect of repair by patch in composite is very distinct, considering the intensities of stresses which decrease for each repair corresponding to the plate not repaired, therefore, the patch in composite dampens the stress field induced at the crack tip and causes a reduction in stresses. The repair with the Bore / epoxy composite patch is more effective than the Carbon/Epoxy patch, this is due to the mechanical properties and the various characteristics specific to boron/Epoxy which gives very significant and very effective results for the repai

Numerical simulation of a crack emanating from a micro-cavity in the orthopedic cement by technical sub modeling of total hip prosthesis

PMMA has important micro structural heterogeneities such as cavities, and its elastic behavior is greatly affected by the presence of defects that may imply its weakening and cause failure. In areas of high concentrations of stress and due to the presence of cavities, micro cracks appear after crushing cavities due to patient movements, and grow and weld to each other until they form a macro     fissure that propagates until the total removal of the prosthesis.. In this study, the existence of a crack emanating from  a cavity with a diameter of 0.7 mm was assumed; our assessment takes into account two parameters, the position of the crack in the cement and we calculated the stress intensity factor (SIF) in the proximal part of orthopedic cement

Contributions of Information and communication technologies to industrialization of additive manufacturing

Additive manufacturing is in clear progress in the field of civil engineering construction, essentially boosting by the development of new information and communication technologies. For better industrialization of the use of this technique, in-situ control of products manufactured along the production line is a major issue. In this work we were able to supervise the quality of printed object along the process by comparing the target values and those measured by image processing obtained by a camera installed in the printing device. We have developed a program that allows us to measure the deformations of the different layers and thus to assess the difference between the values of the target ratings and those achieved. This deviation is defined as a criterion for validating piece conformity and can also be used to adapt the process parameters

High Expression of HLA-G in Ovarian Carcinomatosis: The Role of Interleukin-1β

The present study focuses on the influence of the tumor microenvironment on the expression of HLA-G in ovarian cancer and its impact on immune cells. We used carcinomatosis fluids (n = 16) collected from patients diagnosed with epithelial ovarian cancer, detected by an increase in CA125 levels. Our results indicate that HLA-G is expressed by 1) ascitic cell clusters, 2) stromal cells (hospicells) extracted from cancer cell clusters, and 3) cancer cell lines and tumor cells. The origin of HLA-G was linked to inflammatory cytokines present in the cancer microenvironment. In parallel, the ascitic fluid of patients with ovarian cancer contains soluble HLA-G (sHLA-G). The mesothelial cell layer and submesothelial tissues, as well as the immune cell infiltrate, do not secrete HLA-G. In contrast, sHLA-G is absorbed by peritoneal tissues along with mesothelial layers as well as immune cell infiltrates. We demonstrated that interleukin-1β along with TGF-β can be a major HLA-G–inducing factor that upregulates HLA-G expression through the NF-κB pathway. The level of HLA-G in ascites correlated positively with the expression of T regulatory (T-regs) cells, while it negatively correlated with the expression of natural killer and memory cells in tumor-infiltrating immune cells. In conclusion, the production of HLA-G is associated with the presence of inflammatory cytokines and is strongly correlated with microenvironment tolerant cells such as T-regs and diminution of NK and memory T cells