Thermo-mechanical stress of bonded wires used in high power modules with alternating and direct current modes

Today, power electronic reliability is a main subject of interest for many companies and laboratories. The main process leading to the IGBT failure is the cycling thermal stress. Indeed the current flow induce local heating and then mechanical stress. This paper deals with electro thermal stress under steady and transient current states. The main objective is to test bonded wires with active current cycle. Consequently, the thermo mechanical stress is obtained. A numerical 3D finite element model is presented and some experimental results are given. Indeed an infrared system monitors the temperature dispatching from an experimental test bench under active current cycle. The overall study is a first step before a global simulation (electrical thermal-mechanical) in order to optimize some geometric parameters of the packaging

Mechanical stress induced by electromagnetic forces on wire bonds of high power modules

This paper concerns the analytical determination and experimental characterization of electromagnetic forces exerted on high power IGBT wire bonds

Crassicauda boopis in a fin whale (Balaenoptera physalus) ship-struck in the eastern North Atlantic Ocean

On 9 November 2015, a juvenile male fin whale of 11·60 m length was observed on the bulb of a merchant vessel in the Channel Terneuzen – Ghent (The Netherlands – Belgium). A severe parasitosis was present in the right heart ventricle and caudal caval vein. Parasites were identified as Crassicauda boopis based on macroscopic and microscopic observations. The sequence of the 18S rRNA gene obtained from the parasite samples was 100% similar to the sequence of the 18S rRNA gene from Crassicauda magna available on GenBank. While adults of C. boopis and C. magna are morphologically distinct and found at different locations in the body, the molecular analysis of the 18S rRNA gene seems insufficient for reliable species identification. Although numerous C. boopis were found, the cause of death was identified as due to the collision with the ship, as suggested by the presence of a large haematoma, and the absence of evidence of renal failure. The young age of this whale and the absence of severe chronic reaction may suggest that the infestation was not yet at an advanced chronic stage

Contribution of ambient vibration recordings (Free-field and buildings) for post-seismic analysis: the case of the Mw 7.3 MARTINIQUE (French lesser ANTILLES) earthquake, november 29, 2007

Following the Mw 7.3 Martinique earthquake, November 29th, 2007, a post-seismic survey was conducted by the Bureau Central Sismologique Français (BCSF) for macroseismic intensities assessment. In addition to the inventories, ambient vibration recordings were performed close to the particularly damaged zones in the free-field and the buildings. The objective of the paper is to show the relevancy of performing ambient vibration recordings for post-earthquake surveys. The analyses of the recordings aim at explaining the variability of the damages through site effects, structure vulnerability or resonance phenomena and to help the characterization of the post-seismic building integrity. In three sites prone to site effects, we suspect damage to be related to a concordance between soil fundamental frequency and building resonance frequency. Besides, the recordings of ambient vibrations at La Trinité hospital before and after the earthquake allow us to quantify the damage due to earthquake in terms of stiffness loss

Seismic hazard assessment in Menton, France: Topographical site effect zoning considering a semi-empirical approach and a Machine Learning scheme

The presence of topography influences the seismic ground motion and may result in strong amplifications, generally at the top of hills and reliefs. The increasing urbanization of hills requires an accurate estimation of these effects even in areas of moderate seismicity. The simplified coefficients provided by the Eurocodes8 do not depend on the frequency and underestimate the amplification in many situations, which justifies the development of new methods based on easily accessible data. The city of Menton, located in the southeast of France, between the Alps and the Ligurian basin, is one of the most exposed metropolitan cities. We propose a study of topographic effects applied to the Menton area. Topographic amplification is calculated, on a wide frequency band, using the Frequency-Scaled Curvature method, from a DEM and an average value of the shear wave velocity. We then propose to apply an automatic clustering approach to classify the amplification curves into five groups with similar properties. We then deduce a first microzonation map of the topographic effects in the Menton area