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Southfield, MI, United States

Halfpenny A.,Advanced Manufacturing Park Technology Center | Pompetzki M.,HBM nCode Products
SAE International Journal of Materials and Manufacturing

Proving grounds are an extremely efficient means of qualifying the durability of vehicle components. They accelerate damage accumulation rates so failures are detectable in a very short period of time. It is important that proving ground damage is correlated with target customer usage. It is also important to determine the most efficient use of the proving ground in order to meet project targets and minimize overall development costs. This paper describes the latest techniques for proving ground correlation and optimization. Acceleration, strain, wheel force and other types of data are collected on a vehicle as it traverses different proving ground surfaces. Comparable data are also collected from instrumented 'customer' vehicles. The objective of the analysis is to determine which mixture of proving ground surfaces offers the best representation of customer usage while minimizing the total test time. Prior to the optimization stage, time series data must be characterized and reduced to an efficient format. Techniques such as rainflow cycle counting and level crossing are discussed and recommendations are made on the merits of each approach. A new technique based on a damage-weighted frequency spectrum is introduced. This offers significant improvements in damage-based optimization when used with acceleration measurements. The proving ground schedule will tend to be more severely damaging in some components than others. The paper discusses the choice of measurement location in optimizing overall vehicle damage. It also describes how to establish which components are under-tested (i.e. not expected to fail) and which are over-tested (i.e. fail early) in the proving ground schedule. © 2011 SAE International. Source

Pompetzki M.,HBM nCode Products | Dabell B.,HBM nCode Products | Lin X.,HBM nCode Products
SDHM Structural Durability and Health Monitoring

Structural integrity in terms of automotive durability is a detailed process that incorporates many technical areas. The current durability process for automotive applications involves understanding operational load inputs, the stresses and strains caused and the response of the material, performing fatigue tests, calculating fatigue life and interpreting results. There are many variations on this process depending on the application, materials, available information, methods, etc. This paper presents a general approach for the durability process in automotive applications and highlights a number of new advancements. These advancements include understanding the service operating load conditions through improved usage based monitoring, characterizing new materials together with their associated damage models, enhancing and automating data manipulation through straightforward, consistent and rapid process based analysis, creating test profiles for random loading and accelerating CAE based durability analysis. The impact and importance of the advancements is illustrated by reference to each part of the durability process as well as the process itself. Copyright © 2010 Tech Science Press. Source

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