THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Data Mining Practical Machine Learning Tools and Techniques

This book, written by two major figures in adaptive control, provides a wealth of material for researchers, practitioners, and students. While some researchers in adaptive control may note the absence of a particular topic, the book‘s scope represents a high-gain instrument. It can be used by designers of control systems to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs. The book is strongly recommended to anyone interested in adaptive control.

Adaptive Control

A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

Effect of Temperature

____ : ..... '"i-t.-

Open-die forging is an incremental bulk metal forming process providing excellent mechanical properties and lifetime. Therefore, open-die forged parts are used for highly loaded application purposes e.g., in energy technology. However, the range of producible geometries in open-die forging is limited mainly to long and straight workpieces with simple cross-sections. Here, open-die forging with superimposed manipulator displacements offers a large potential for the production of curved workpieces. The new process concept is based on the idea, that the manipulator, originally designed as a handling device, is now actively used to control the material flow towards an intended final geometry. The idea was successfully realized for the production of curved workpieces by open-die forging. The hereby-presented investigations now aim at an analysis of the process limits for bending in vertical direction. Based on a fundamental analysis, a tilting of the samples between the forging dies and an undesired contact of the curvature with the forging die were identified as main process limits leading to a reduction of the curvature. By numerical simulation and fundamental geometric analysis, a process window was identified, where the occurrence of process limits and thus a reduction of curvature can be avoided. Finally, experimental validation was carried out at the industrially scaled open-die forging setup at IBF proving that the identified process window can successfully be realized.

Analysis of process limits for open-die forging with superimposed manipulator displacements in vertical direction

The industrial application of incremental sheet forming (ISF) still stays behind the expectations due to the low geometrical accuracy of the produced parts as well as the insufficient predictability of the forming result. This is due to the fact that some mechanisms which cause the geometrical deviations are not fully understood. Many investigations have already been carried out to determine which types of stresses induced by ISF influence the forming result. This paper tries to systematically categorize selected typical geometric deviations and to review their underlying mechanisms based on current literature as well as their own experience. The intention is to provide a structured basis for future scientific discussion and to stimulate an exchange of experience, with the goal that a better understanding may help to improve the geometrical accuracy of parts manufactured by incremental sheet forming.

On the Geometrical Accuracy in Incremental Sheet Forming

Lightweight design is a major driving force of innovation, especially in the automotive industry. Using hybrid components made of two or more different materials is one approach to reduce the vehicles weight and decrease fuel consumption. As a possible way to increase the stiffness of multi-material components, this paper presents a process chain to produce such components made of steel sheets and high-pressure die cast aluminium. Prior to the casting sequence the steel sheets are structured in a modified rolling process which enables continuous interlocking with the aluminium. Two structures manufactured by this rolling process are tested. The first one is a channel like structure and the second one is a channel like structure with undercuts. These undercuts enable the formation of small anchors when the molten aluminium fills them. The correlation between thickness reduction during rolling and the shape of the resulting structure was evaluated for both structures. It can be stated that channels with a d...

Interlocking multi-material components made of structured steel sheets and high-pressure die cast aluminium

Iron–silicon alloys with up to 6.5 wt.% Si offer an improvement of soft magnetic properties in electrical steels compared to conventional electrical steel grades. However, steels with high Si contents are very brittle and cannot be produced by cold rolling. In addition to solid solution hardening, it is assumed that the B2- and DO3-superlattice structures are responsible for the poor cold workability. In this work, two cast strips with 6.0 wt.% Si were successfully produced by the twin roll strip casting process and cooled differently by secondary cooling. The aim of the different cooling strategies was to suppress the formation of the embrittling superlattice structures and thus enable further processing by cold rolling. A comprehensive material characterization allows for the understanding of the influence of casting parameters and cooling strategies on segregation, microstructure and superlattice structure. The results show that both cooling strategies are not sufficient to prevent the formation of B2- and DO3-structures. Although the dark field images show a condition which is far from equilibrium, the achieved condition is not sufficient to ensure cold processing of the material.

Gerhard Hirt

Papers

Analysis of process limits for open-die forging with superimposed manipulator displacements in vertical direction

On the Geometrical Accuracy in Incremental Sheet Forming

Interlocking multi-material components made of structured steel sheets and high-pressure die cast aluminium

Twin Roll Casting and Secondary Cooling of 6.0 wt.% Silicon Steel

Process and materials modeling in metal forming