Evaluation and comparison of surface defects on a simplified model for the area around the fuel filler lid by simulation and experiments

There is a serious need in the automotive industry to predict surface defects in outer panels. Measures to prevent these defects can not be taken until a test part has been manufactured. This costs a lot in time and money. Within the present project stamping tools for a model part resembling the area around the fuel filler lid was developed. This is an area of the outer surface of a car, which is particularly sensitive for surface defects. Based on this model both experiments and sheet-metal-forming simulations were performed and the results were compared. The result showed that the simulations were able to predict the location of the defects but the magnitudes of the defects were not sufficiently accurate. The defects that occurred were more like waves than small localised defects at the corners, “teddy bear ears”. These defects could be seen in both the experiments and the simulations

Numerical and experimental evaluation of springback in a front side member

In this study, a part of an automotive side front section (front side member inner) was studied and a comparison both regarding material behaviour and of accuracy of the FE simulations was made. Mild steel, Rephos steel and TRIP700 were compared both experimentally and numerically. The results showed that TRIP steel has a significantly larger springback than the other materials. Furthermore, the FE simulations overestimate the twisting in this part for all materials, with the TRIP material showing the largest deviation between the experiments and the simulations. The prediction of punch forces was, however, accurate for all materials

Information Exchange within the area of tool design and sheet-metal-forming simulations

Today, shortened lead-times in the automotive industry have raised requirements on rapid information exchange. The increased use and access to the Internet have created possibilities to transfer information to people independent of location. This development, together with the increased speed in the portable computer technology, has opened possibilities for bringing results from sheet-metal-forming simulations directly to the customer. Previously, the results were presented with pictures; now it is possible to use animations. The only requirement is to have access to a post-processor or a viewer that is powerful enough to handle the results. The advantage with animated results is the improved possibilities to follow the sheet-metal-forming process. In this project, the methodology for reporting results from sheet-metal-forming simulations at Volvo Cars Body Components is studied. A potential for improvement would be possible if the reporting procedure is changed from paper copies to a database structure. In the database the results should be stored as files with animated results that the user is able to rotate and zoom. This methodology will contribute to faster and more accurate decisions because it will be based on current information and the user could easily analyse the results without access to special programs

Comparison of sheet-metal-forming simulation and try-out tools in the design of a forming tool

Today, sheet-metal-forming simulation is a powerful technique for predicting the formability of automotive parts. Compared with traditional methods such as the use of try-out tools, sheet-metal-forming simulation enables a significant increase in the number of tool designs that can be tested before hard tools are manufactured. Another advantage of sheet-metal-forming simulation is the possibility to use it at an early stage of the design process, for example in the preliminary design phase. Today, the accuracy of the results in sheet-metal-forming simulation is high enough to replace the use of try-out tools to a great extent. At Volvo Car Corporation, Body Components, where this study has been carried out, sheet-metal-forming simulation is used as an integrated part in the process of tool design and tool production

Simulation and verification of different parameters effect on springback results

Today, simulation of springback has still not reached enough accuracy for acceptance as a production tool in the automotive industry. Further investigations need to be done in order to understand how to improve the results in an efficient way. In order to investigate which parameters that are important for the accuracy in a springback simulation, a parameter study of a U-shaped rail was performed. In the literature several similar studies can be found, but few of them have been analysing the effect of the stress variation. In our investigation these were studied together with the geometrical springback. In order to see the effect of different restraining conditions, five different blank holder forces were applied. Three different materials were studied both experimentally and numerically. The analysed materials were: a mild steel, an extra high strength steel and an aluminium grade. It can be concluded that several of the studied parameters show small effect on the springback results whereas other parameters show significant influence, such as element size in blank and tool and choice of hardening law. The result showed good agreement for the case, which were tuned in to experimental results. The materials showed that different settings were needed for the different materials

Simulation of the forming and assembling process of sheet metal assembly

A sheet metal assembly must meet functional, manufacturing, and sometimes also esthetical requirements. The properties of the assembly are to a large extent affected by the manufacturing process, i.e. the forming processes of the sheet metal components and the subsequent assembling sub-processes. It is of a great industrial interest to be able to predict the properties of the assembly at an early design stage. This paper presents a methodology, based on Finite Element simulations, which makes it possible to accurately predict the properties of a sheet metal assembly. Each forming process of the individual components is simulated, and all properties affected by the forming process are included in the subsequent simulations of the assembling process. Thus, this methodology makes it possible to optimize both the functional properties of the assembly and also its manufacturing process considering all mechanical effects introduced by the individual manufacturing processes. A case study of a semi-industrial assembly has been conducted and the simulation results agree well to experimental data

Gene Expression Profiling and Chromatin Immunoprecipitation Identify DBN1, SETMAR and HIG2 as Direct Targets of SOX11 in Mantle Cell Lymphoma

The SRY (sex determining region Y)-box 11 (SOX11) gene, located on chromosome 2p25, encodes for a transcription factor that is involved in tissue remodeling during embryogenesis and is crucial for neurogenesis. The role for SOX11 in hematopoiesis has not yet been defined. Two genes under direct control of SOX11 are the class- III β-tubulin gene (TUBB3) in neural cells and the transcription factor TEA domain family member 2 (TEAD2) in neural and mesenchymal progenitor cells. Normal, mature lymphocytes lack SOX11 but express SOX4, another member of the same group of SOX transcription factors. We and others recently identified SOX11 as aberrantly expressed in mantle cell lymphoma (MCL). Since SOX11 is variably expressed in MCL it may not be essential for tumorigenesis, but may carry prognostic information. Currently, no specific functional effects have been linked to SOX11 expression in MCL and it is not known which genes are under influence of SOX11 in lymphoma. In this study we found variable expression of SOX11, SOX4 and SOX12 mRNA in mantle cell lymphoma cell lines. Downregulation of SOX11 expression by siRNA verified that SOX11 controlled the expression of the gene TUBB3 in the MCL cell line Granta 519. Furthermore we identified, by global gene expression analysis, 26 new target genes influenced by siRNA SOX11 downmodulation. Among these genes, DBN1, SETMAR and HIG2 were found to be significantly correlated to SOX11 expression in two cohorts of primary mantle cell lymphomas. Chromatin immunoprecipitation (ChIP) analysis showed that these genes are direct targets of the SOX11 protein. In spite of almost complete downregulation of the SOX11 protein no significant effects on Granta 519 cell proliferation or survival in short term in vitro experiments was found. In summary we have identified a number of genes influenced by SOX11 expression in MCL cell lines and primary MCL. Among these genes, DBN1, SETMAR and HIG2 are direct transcriptional targets of the SOX11 protein

Endothelin Receptor A Antagonism Attenuates Renal Medullary Blood Flow Impairment in Endotoxemic Pigs

BACKGROUND: Endothelin-1 is a potent endogenous vasoconstrictor that contributes to renal microcirculatory impairment during endotoxemia and sepsis. Here we investigated if the renal circulatory and metabolic effects of endothelin during endotoxemia are mediated through activation of endothelin-A receptors. METHODS AND FINDINGS: A randomized experimental study was performed with anesthetized and mechanically ventilated pigs subjected to Escherichia coli endotoxin infusion for five hours. After two hours the animals were treated with the selective endothelin receptor type A antagonist TBC 3711 (2 mg⋅kg(-1), n = 8) or served as endotoxin-treated controls (n = 8). Renal artery blood flow, diuresis and creatinine clearance decreased in response to endotoxemia. Perfusion in the cortex, as measured by laser doppler flowmetry, was reduced in both groups, but TBC 3711 attenuated the decrease in the medulla (p = 0.002). Compared to control, TBC 3711 reduced renal oxygen extraction as well as cortical and medullary lactate/pyruvate ratios (p<0.05) measured by microdialysis. Furthermore, TBC 3711 attenuated the decline in renal cortical interstitial glucose levels (p = 0.02) and increased medullary pyruvate levels (p = 0.03). Decreased creatinine clearance and oliguria were present in both groups without any significant difference. CONCLUSIONS: These results suggest that endothelin released during endotoxemia acts via endothelin A receptors to impair renal medullary blood flow causing ischemia. Reduced renal oxygen extraction and cortical levels of lactate by TBC 3711, without effects on cortical blood flow, further suggest additional metabolic effects of endothelin type A receptor activation in this model of endotoxin induced acute kidney injury