Tim Davis

• PhD CEng
• Professor at University of Warwick

We apply Dimensional analysis to Meyer's 1953 Black Cherry tree data (sometimes referred to as the Minitab cherry tree data) to predict trunk volume as a function of trunk diameter and tree height. We show how are model has wide applicability in forestry

Using the FMEA to achieve failure mode avoidance

We explore the concept of parameter design applied to the production of glass beads in the manufacture of metal-encapsulated transistors. The main motivation is to complete the analysis hinted at in the original publication by Jim Morrison in 1957, which was an early example of discussing the idea of transmitted variation in engineering design, and...

We explore the concept of parameter design applied to the production of glass beads in the manufacture of metal-encapsulated transistors. The main motivation is to complete the analysis hinted at in the original publication by Jim Morrison in 1957, which was an early example of discussing the idea of transmitted variation in engineering design, and...

This is a follow up article to Reliability Disasters by N Doganaksoy, WQ Meeker & GJ Hahn, published in Quality Progress, August 2020 which will be submitted to Quality Progress in due course https://asq.org/quality-progress/articles/reliability-disasters?id=38c2aa802bad44ceb72b550a71054fa1

This short discussion article is a commentary on a paper by Alyson Wilson of NCSU called Bayesian Reliability - Combining Information, which was presented at the 4th Hunter Conference hosted by the University of Waterloo Toronto Canada, March 2016

a pre-print and longer version of the published article

This is a longer version of the paper that appeared in Technometrics (2013)

Failure modes are an inevitable consequence of the Product Development (PD) process. They are crucial in their impact on product design since they affect product quality and costs because of the requirement for counter measures, thus potentially imposing high risks on any organization engaged in pro duct development in terms of customer dissatisfac...

Failure modes are an inevitable consequence of the Product Development (PD) process. They are crucial in their impact on product design since they affect product quality and costs because of the requirement for counter measures, thus potentially imposing high risks on any organization engaged in product development in terms of customer dissatisfact...

Dimensional Analysis (DA) is a well-developed widely-employed methodology in the physical and engineering sciences. The application of dimensional analysis in statistics leads to three ad-vantages: (1) the reduction of the number of potential causal factors that we need to consider, (2) the analytical insights into the relations among variables tha...

The application of dimensional analysis to solving engineering problems is discussed, using the Minitab cherry tree data, and the paper helicopter as illustrative examples. Particular emphasis is placed on the iterative and convergent nature of engineering investigations. We also make some connections between dimensional analysis and sliding levels...

Probability distributions traditionally used in reliability analysis (e.g. exponential, Weibull, lognormal, normal, gamma and inverse Gaussian) do not always provide enough flexibility to model real-world lifetime data. Considered in this paper is a quadratic spline with a single free knot as a model of the cumulative hazard function for increasing...

Symmetry and parsimony, together with unification through synthesis are important principles that govern the character of physical law. We show how these principles can be applied to engineering to develop an approach to reliability, and engineering in general, that centres on the identification, detection, and avoidance of failure modes through de...

Product recall notices in shops, newspapers and elsewhere inform us now and then of children's toys that might be dangerous or electrical goods that could catch fire. You or I might describe that as faulty design. Tim Davis calls it an “escaped failure mode”—and he is against it. His world is not toys or electrical goods, but vehicles, where failur...

Abstract: Symmetry, parsimony, and unification are important principles that govern the character of physical law. We show how these principles can be applied in engineering to develop a framework that centres on the identification and avoidance of failure modes through design. To support this approach, a definition of reliability, not in terms of...

In this paper we discuss avoiding failure modes due to lack of robustness. It is proposed that robustness should be measured through a parameter in a transfer function, as opposed to a signal-to-noise ratio. A case study on engine starting is used to illustrate the idea.

The paper considers an empirical approach to the root-cause analysis of a certain kind of automobile tire failure. Tire life data are obtained from a laboratory test, which is developed to duplicate field failures. A number of parameters related to tire geometry and physical properties are selected as explanatory variables that potentially affect a...

Engine mapping is the term used in the automotive industry when modeling engine outputs; the current methods offer considerable scope for improvement. The engineering problem and the present approach are described in some detail as necessary background. A two-stage modeling approach is presented and demonstrated on a small dataset designed and coll...

Smith (1991) presents a paper proposing the use of Weibull regression models to establish dependence of failure data (usually times) on covariates related to the design of the test specimens and test procedures. In his article Smith made the point that good experimental design was as important in reliability applications as elsewhere, and in view o...

Efficient data acquisition and effective data analysis form the corner stone of a sound decision making process. However being data driven may be a good management principle but a pre-requisite is that engineers and managers have knowledge of the nature of measurement and variability. All systems from administration, to engineering, to manufacturin...

Efficient data acquisition and effective data analysis form the corner stone of a sound decision making process. However being data driven may be a good management principle but a pre-requisite is that engineers and managers have knowledge of the nature of measurement and variability. All systems from administration, to engineering, to manufacturin...

The Box–Behnken three-level designs have proved useful for fitting second-order response surfaces to experimental data. Here, we discuss an aspect of their value in the detection of lack of model fit. The degrees of freedom in excess of those needed to fit the model can be used advantageously for contrasts which estimate certain higher-order depart...

Engineering, Quality and Experimental Design is a unique text which will aid design and production engineers in their efforts to improve quality and productivity. Keeping formulae to a minimum, the authors explain the fundamental ideas involved in planning efficient experiments and making good use of the results. The book presents the engineer with...

The idle column method, proposed by Taguchi, enables a two-level orthogonal array to be used as the basis of a mixed-level fractional factorial experiment. The resulting designs are not orthogonal but can in some circumstances be described as nearly orthogonal. The method must be applied with care, because an apparently minor change in the techniqu...

The idle column method, proposed by Taguchi, enables a two-level orthogonal array to be used as the basis of a mixed-level fractional factorial experiment. The resulting designs are not orthogonal but can in some circumstances be described as nearly orthogonal. The method must be applied with care, because an apparently minor change in the techniqu...

A general expression for the non-parametric likelihood in competing risk survival analysis is derived. Unlike earlier forms, it can be correctly applied when there are tied failure times of different types. A tyre testing data set and application is given.

A general expression for the non-parametric likelihood in competing risk survival analysis is derived. Unlike earlier forms, it can be correctly applied when there are tied failure times of different types. A tyre testing data set and application is given.