Engine Oil- Crankshaft Interaction Fem Modelling of an Air-Cooled Diesel Engine under Dynamic Severe Functioning Conditions

Taking into account the interaction between the engine oil and the crankshaft to model crankshaft thermomechanical behavior under dynamic loading is very important. In particular, when the crankshaft is working in severe conditions. This paper deal with an air cooled direct injection-type engine crankshaft thermomechanical FEM modelling account for engine oil-cranks half interaction in severe working conditions. As case of application we consider the diesel engine Deutz F8L413. The model takes into account 2 forced convectives heat flux: engine oil and crankcase air. The severe mechanical and thermal characteristics of engine are experimentally measured on a bench test equipped with a hydraulic brake. The temperature distribution inside the crankshaft was computed using the measured temperature as boundary conditions. The most thermo-mechanical stressed zones of the crankshaft have been determined. The fatigue resistance of the crankshaft under thermo-mechanical conditions was examined using Dang-Van multi-axial fatigue criteria. To prove our model efficiency, we have compared crankshaft damage in service to the numerical simulation results. It was found the breakage occurred in an area where the numerical simulations give the highest stresses.

Assessment of a Rock Pillar Failure by Using Change Detection Analysis and FEM Modelling

In this paper, various methods have been used to control and evaluate engineering difficulties in mining accurately. Different unstable scenarios occurring at the surfaces of underground mine walls, have been identified by comparing 3D terrestrial laser scanning surveys and subsequent point cloud 3D analysis. These techniques, combined with a change detection analysis approach and the integration of rock mechanics’ modelling, represent an asset for the assessment and management of the risk in mining. The change detection analysis can be used as control of mining and industrial processes as well as to identify valid model scenarios for establishing possible failure causes. A pillar spalling failure has been identified in an Italian underground marble quarry and this topic represents the basis of the present paper. A Finite-Element Method was used to verify the occurrence of relatively high-stress concentrations in the pillar. The FEM modelling revealed that stresses in the proximity of the pillar may have sufficient magnitude to induce cracks growth and spalling failure.

FEM Modelling Approaches of Bolt Connections for the Dynamic Analyses of an Automotive Engine

Three different finite element method (FEM) modelling approaches of bolt connections of a four-stroke, four-cylinder petrol engine are presented, and the related results compared in terms of preprocessing time and accuracy. A full 3D modelling of the bolt connections was preliminarily validated through a comparison with experimental test data available for the whole engine. Two further modelling approaches, a 1D approach and a contact-based (0D) approach, were benchmarked considering their influence on the accuracy for the dynamic analysis of an engine. Each of the three approaches presented pros and cons, even if the 1D modelling could be envisaged as the recommended one in most of cases.

Modelling Considerations for Coupled Lines in CMOS Back-End-Of-Line at mm-Wave Frequencies

<p>We investigate the effect of passivation contouring, surface roughness, and sidewall etch tapering on the FEM modelling accuracy of mm-wave couplers in CMOS BEOL. It is found that accurate passivation contouring leads to a marginal improvement of 0.15 dB in peak coupling prediction accuracy, but introducing a sidewall taper of 104ᵒ can improve the prediction of peak coupling by up to 0.37 dB. Including surface roughness of 5 % and 10 % of metal thickness did not have a notable improvement on prediction of peak coupling.</p>

Modelling Considerations for Coupled Lines in CMOS Back-End-Of-Line at mm-Wave Frequencies

<p>We investigate the effect of passivation contouring, surface roughness, and sidewall etch tapering on the FEM modelling accuracy of mm-wave couplers in CMOS BEOL. It is found that accurate passivation contouring leads to a marginal improvement of 0.15 dB in peak coupling prediction accuracy, but introducing a sidewall taper of 104ᵒ can improve the prediction of peak coupling by up to 0.37 dB. Including surface roughness of 5 % and 10 % of metal thickness did not have a notable improvement on prediction of peak coupling.</p>