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

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Asymmetric incremental sheet forming (AISF) is a relatively new manufacturing process for the production of low volumes of sheet metal parts. Forming is accomplished by the CNC controlled movements of a simple ball‐headed tool that follows a 3D trajectory to gradually shape a sheet metal blank. The local plastic deformation under the tool leads to a number of challenges for the Finite Element Modeling. Previous work indicates that implicit finite element methods are at present not efficient enough to allow for the simulation of AISF for industrially relevant parts, mostly due to the fact that the moving contact requires a very small time step. Explicit Finite Element methods can be speeded up by means of mass or load scaling to enable the simulation of large scale sheet metal forming problems, even for AISF. However, it is well known that the methods used to speed up the FE calculations can entail poor results when dynamic effects start to dominate the solution. Typically, the ratio of kinetic to internal energy is used as an assessment of the influence of dynamical effects. It has already been shown in the past that this global criterion can easily be violated locally for a patch of elements of the finite element mesh. This is particularly important for AISF with its highly localised loading and complex tool kinematics. The present paper details an investigation of dynamical effects in explicit Finite Element analysis of AISF. The interplay of mass or time scaling scheme and the smoothness of the tool trajectory is analysed with respect to the resulting errors. Models for tool path generation will be presented allowing for a generation of tool trajectories with predefined maximum speed and acceleration. Based on this, a strategy for error control is proposed which helps reduce the time for setting up reliable explicit finite element models for AISF.

Error Analysis In Explicit Finite Element Analysis Of Incremental Sheet Forming

The present paper focuses on a new methodology to quantitatively evaluate finite element calculations on incremental sheet forming (ISF). ISF is a new manufacturing process for prototypes and small lot sizes. In ISF, a part is manufactured by the CNC-driven movement of a simple tool, giving rise to very challenging problems concerning the efficient modeling of the alternating contact conditions and the material's response to the cyclic deformation. The quantitative validation of the finite element analysis is achieved by an optical deformation measurement system which has been enhanced by a new calibration procedure, yielding a precisely defined local coordinate system for deformation measurements during forming. In combination with mapping algorithms for large point sets, this allows for a quantitative validation of process simulations and material input data.

Quantitative Validation of FEM Simulations for Incremental Sheet Forming Using Optical Deformation Measurement

In this work, a Fe-23Mn-0.3C-1Al high manganese twinning-induced plasticity (TWIP) steel is subjected to varying warm rolling procedures in order to increase the yield strength and maintain a notable ductility. A comprehensive material characterization allows for the understanding of the activated deformation mechanisms and their impact on the resulting microstructure, texture, and mechanical properties. The results show a significant enhancement of the yield strength compared to a fully recrystallized Fe-23Mn-0.3C-1Al steel. This behavior is mainly dominated by the change of the active deformation mechanisms during rolling. Deformation twinning is very pronounced at lower temperatures, whereas this mechanism is suppressed at 500 °C and a thickness reduction of up to 50%. The mechanical properties can be tailored by adjusting rolling temperature and thickness reduction to desired applications.

https://www.mdpi.com/2075-4701/9/7/797/pdf

The Influence of Warm Rolling on Microstructure and Deformation Behavior of High Manganese Steels

Friction and wear of lubricated machine elements can be reduced by the introduction of lubrication pockets produced by surface texturing. Different manufacturing methods can be taken into consideration whereas a forming process offers the possibility for mass production. Hot micro coining is a forming process, which allows manufacturing of surface textures with different shapes and dimensions into a flat and deformable material, e.g. seals made of steel. In this work hemispherical and ellipsoid pockets with a maximum depth of 100 µm have been embossed into stainless steel (AISI 304). To ensure that the used process parameters will not lead to tool damage, Finite Element simulations were performed and experimentally verified. First tribological experiments were conducted on a ball-on-disk tribometer in order to study the tribological properties of hemispherical structures with pockets depths of 50 and 100 µm. Different sliding velocities were applied to study the coefficient of friction and wear volume for different lubrication conditions. A comparison between coined and not‑coined specimens demonstrates that the micro coined surface textures lead to a significant reduction in the wear volume at boundary and mixed lubrication conditions.

Manufacturing and Tribological Investigation of Hot Micro-Coined Lubrication Pockets

Nowadays, optimization of non-oriented (NO) electrical steels toward lower iron-loss, improved, and isotropic magnetizability is critical to the improvement of rotating electrical machines. The whole production process chain adjusts the microstructure evolution, e.g., grain size and crystallographic texture, determining the magnetic properties. In particular, the interdependence of raw material properties and the resulting mechanical stress distribution during final assembly, e.g., punching, leading to magnetic property deterioration is crucial for the optimization of NO steel properties of rotating machines. This paper studies the effect of different cold rolling strategies, annealing treatments, and sheet metal blanking (punching) regarding microstructure evolution, magnetic properties, and deterioration.

Gerhard Hirt

Papers

Error Analysis In Explicit Finite Element Analysis Of Incremental Sheet Forming

Quantitative Validation of FEM Simulations for Incremental Sheet Forming Using Optical Deformation Measurement

The Influence of Warm Rolling on Microstructure and Deformation Behavior of High Manganese Steels

Manufacturing and Tribological Investigation of Hot Micro-Coined Lubrication Pockets

Effect of the Interdependence of Cold Rolling Strategies and Subsequent Punching on Magnetic Properties of NO Steel Sheets