Dynamic behaviour of AA 2024 under blast loading : experiments and simulations

The dynamic behaviour of AA2024-T3 is investigated. Dynamic tensile tests using a servo-hydraulic and a light weight shock testing machine (LSM) have been performed. The servo-hydraulic test machine proves to be more reliable and reaches higher strain rates. Neither test revealed any strain rate effect of AA2024-T3. Two types of fracture tests were carried out to determine the dynamic crack propagation behaviour of this alloy, using prestressed plates and pressurized barrels, both with the help of explosives. The prestressed plates proved to be not suitable, whereas the barrel tests were quite reliable, allowing to measure the crack speeds. Computer simulations with a user defined, rate dependent cohesive zone model were in agreement with experiments, capturing the rate toughening effect

Reduced glomerular endothelial thrombomodulin is associated with glomerular macrophage infiltration in diabetic nephropathy

The endothelial glycoprotein thrombomodulin regulates coagulation, inflammation, and apoptosis. In diabetic mice, reduced thrombomodulin function results in diabetic nephropathy (DN). Furthermore, thrombomodulin treatment reduces renal inflammation and fibrosis. Herein, thrombomodulin expression was examined in human kidney samples to investigate the possibility of targeting thrombomodulin in patients with DN. Glomerular thrombomodulin was analyzed together with the number of glomerular macrophages in 90 autopsied diabetic cases with DN, 55 autopsied diabetic cases without DN, and 37 autopsied cases without diabetes or kidney disease. Thrombomodulin mRNA was measured in glomeruli microdissected from renal biopsies from patients with DN and nondiabetic controls. Finally, glomerular thrombomodulin was measured in diabetic mice following treatment with the selective endothelin A receptor (ETAR) blocker, atrasentan. In diabetic patients, glomerular thrombomodulin expression was increased at the mRNA level, but decreased at the protein level, compared with nondiabetic controls. Reduced glomerular thrombomodulin was associated with an increased glomerular influx of macrophages. Blocking the ETAR with atrasentan restored glomerular thrombomodulin protein levels in diabetic mice to normal levels. The reduction in glomerular thrombomodulin in diabetes likely serves as an early proinflammatory step in the pathogenesis of DN. Thrombomodulin protein may be cleaved under diabetic conditions, leading to a compensatory increase in transcription. The nephroprotective effects of ETAR antagonists in diabetic patients may be attributed to the restoration of glomerular thrombomodulin.Immunopathology of vascular and renal diseases and of organ and celltransplantationIP1

sFLT1_APOC1_dataset_2019

APOC1 transgenic mice, a mouse model of atopic dermatitis, were transfected with sFLT-1, a VEGF inhibitor. sFLT-1 reversed skin lesions through anti-inflammatory effects

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sFLT1_APOC1_dataset_2019

APOC1 transgenic mice, a mouse model of atopic dermatitis, were transfected with sFLT-1, a VEGF inhibitor. sFLT-1 reversed skin lesions through anti-inflammatory effects.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Underwater shock response analysis of a floating vessel

The response of a surface vessel to underwater shock has been calculated using an explicit finite element analysis. The analysis model is two-dimensional and contains the floating steel structure, a large surrounding water volume and the free surface. The underwater shock is applied in the form of a plane shock wave and cavitation is considered in the analysis. Advanced computer graphics, in particular video animations, provide a powerful and indispensable means for the presentation and evaluation of the analysis result

Dynamic testing of adhesive joints using a shock testing machine

A light-weight shock testing machine, designed for type approval testing of naval equipment up to 300 kg mass, has been modified into a dynamic tensile test rig. This enables to test structural details for high rate dynamic tensile loadings such as occur during underwater shock. The maximum capacity is 200 kN and can be reached within a few milliseconds. This test rig was used for tensile shock tests on three different types of bonded composite-metal joints. Compared to results from quasi-static testing, the shock tests show a considerable increase of tensile strength for two of the three types of connections and a different ranking

The simplified interaction tool for efficient and accurate underwater shock analysis of naval ships

In order to satisfy the need for good quality UNDEX response estimates of naval ships, TNO developed the Simplified Interaction Tool (SIT) for underwater shock analysis. The SIT is a module of user routines linked to LS-DYNA, which generates the UNDEX loading on the wet hull of a 3D finite element model of the ship structure by means of sophisticated physical approximation. This eliminates the need for a 3D mesh of the surrounding water, such as necessary for advanced coupled finite element/hydrocode simulations. The SIT models both the shock wave stage with reflections and cavitation and the subsequent gas bubble loading. The SIT was tuned and validated using experimental data from full-scale ship shock trials. A typical simulation of a detailed 3D finite element model of a naval ship takes only hours for the shock wave stage, against at least days for a comparable coupled simulation. This presentation provides a short overview of the physical approximations of the SIT, recent enhancements and examples of applications

Underwater shock response analysis of a floating cylinder

Three-dimensional simulations were done of a heavy underwater shock trial on a floating cylinder, which was executed in 1996. The analyses were done using the so-called Simplified Interaction Tool, an approximate interaction method developed by TNO as an add-on to LS-DYNA. The analysis was continued beyond cavitation closure into the whipping stage. The simulation results were compared against experimental results from the shock trial as well as previous two-dimensional simulation results using a hydrocode. While the 2D hydrocode analysis provides a principally better simulation of the fluidstructure interaction, the 3D analysis has the capability of modelling the 3D structural details correctly. Comparison against the experimental results shows that the new 3D analysis provides better results