The 12 papers in this techncial paper collection represent research in the areas of welding, riveting, joining, and fastening for automotive applications. Papers focus on the recent advances in the process optimization, analytical solution, numerical modeling, response evaluation as well as static and dynamic testing of traditional resistance spot welds, gas metal arc welds, friction stir spot welds, laser welds, rivets, mounts, adhesives, and fasteners.
Up to now, the reliability achieved by COTS components was largely sufficient for avionics, in terms of failure rate as well as time to failure. With the implementation of new and more integrated technologies (90 nm node, 65 nm and below), the question has arisen of the impact of the new technologies on reliability. It has been stated that the lifetime of these new technologies might decrease. The drift is expected to be technology dependent: integration, technology node, materials, elementary structure choices and process pay a key role. Figures have been published, which gives smaller lifetime than the 30 years generally required for avionics. This would of course impact not only the reliability, but also the maintenance of COTS-based avionics. Hence a new policy should be defined for the whole COTS supply chain. Faced with these impending risks, different methodologies have been developed.
This article characterizes the special features of drilling of CFRP/Titanium and -Aluminium stacks. Simplified theoretic models will show how CFRP/Titanium stacks should be machined without scratches and burn marks contacting carbon. Low axial forces and smart chip removal technology are the main characteristics of the drilling tool technology, optimized to reach H8 quality in one shot operation. Presenter Peter Mueller-Hummel, Cutting Tools Inc.
High Speed Machining of CFRP Parts Investigation of the influence of new geometries, cutting datas and coolant capabilities on the surface finish of CFRP parts. State of the art: Different CFRP grades and machining conditions make geometry adjustments to the tool necessary. Mechanical failures through machining operations can be avoided in most of the cases. New unidirectional CFRP grades and dry machining processes again lead to machining problems. This study investigates new geometries to avoid heat damage with dry maching and air coolant in case of unidirectional CFRP. With help of a thermo camera and the surface investigation with a scanning electron microscope, heat damage can be analysed and therefore new geometries can be developed and tested. Target is to develop a new multi purpose CFRP geometry to meet the requirements of the future. The reduction of different geometries used leads to major cost savings. Presenter Ingo von Puttkamer, Guhring oHG
In a variety of industries there is a growing need to manufacture high quality carbon fibre epoxy matrix composite structures at greater production rates and lower costs than has historically been the case. This has developed into a desire for the automation of the manufacture of components, and in particular the lay-up phase, with Automated Tape Laying (ATL) and Fibre Placement (AFP) the most popular choices. When used for large primary structures there are such potential gains to be had that both techniques have seen rapid implementation into manufacturing environments. But significant concerns remain and these have limited their wider adoption into secondary structure manufacturing, where manual forming of woven broadgoods is dominant. As a result the manufacture of secondary structures is generally explored for costs reduction through drape simulation and lower cost materials.
A combination of laboratory reactor measurements and vehicle FTP testing has been combined to demonstrate a method for diagnosing the formation of NO2 from a diesel oxidation catalyst (DOC). Using small cores from a production DOC and simulated diesel exhaust, the laboratory reactor experiments are used to support a model for DOC chemical reaction kinetics. The model we propose shows that the ability to produce NO2 is chemically linked to the ability of the catalyst to oxidize hydrocarbon (HC). For thermally damaged DOCs, loss of the HC oxidation function is simultaneous with loss of the NO2 production function. Since HC oxidation is the source of heat generated in the DOC under regeneration conditions, we conclude that a diagnostic of the DOC exotherm is able to detect the failure of the DOC to produce NO2. Vehicle emissions data from a 6.6 L Duramax HD pick-up with DOC of various levels of thermal degradation is provided to support the diagnostic concept.
As a result of recommendation from the Augustine Panel, the direction for Human Space Flight has been altered from the original plan referred to as Constellation. NASA's Human Exploration Framework Team (HEFT) proposes the use of a Shuttle Derived Heavy Lift Launch Vehicle (SDLV) and an Orion derived spacecraft (salvaged from Constellation) to support a new flexible direction for space exploration. The SDLV must be developed within an environment of a constrained budget and a preferred fast development schedule. Thus, it has been proposed to utilize existing assets from the Shuttle Program to speed development at a lower cost. These existing assets should not only include structures such as external tanks or solid rockets, but also the Flight Software which has traditionally been a ?long pole? in new development efforts. The avionics and software for the Space Shuttle was primarily developed in the 70's and considered state of the art for that time.
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