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

Digital image correlation for surface deformation measurement: historical developments, recent advances and future goals

Advanced Issues in springback

https://www.tpbin.com/Uploads/Subjects/0611b255-45d7-457a-8988-9c77b24b09c0.pdf

Complex unloading behavior: Nature of the deformation and its consistent constitutive representation

The effects of rolling deformation, rolling temperature and aging treatment on microstructure and mechanical properties of Cu-Cr-Zr alloy were investigated and the relevant influencing mechanism was also discussed in this study. The results showed that the tensile strength of the Cu-Cr-Zr alloy increased with an increase of rolling deformation at room temperature. The elongation to failure of the alloy decreased until the rolling reduction is up to 80% and then increased with the reduction, which is related to the grain orientation change from Copper texture with poor plasticity to the Goss/Brass texture with good plasticity. A large amount of Cr precipitates were identified during rolling at 300 °C in Cu-Cr-Zr alloy, which resulted in much higher electrical conductivity and tensile strength exceeded that of the room-temperature rolling with the rolling reduction over 80%. Aging treatment of 450 °C for 1 h led to the formation of massive Cr and Cu 4 Zr precipitates, which can significantly improve the tensile strength from 591.1 MPa to 669.1 MPa and electrical conductivity from 30.3%IACS to 74.5%IACS of the room-temperature rolled alloy. These results provide a guideline for exploring efficient preparation methods of high-performance Cu-Cr-Zr alloys.

Effect of rolling and aging processes on microstructure and properties of Cu-Cr-Zr alloy

Large deformation measurement scheme for 3D digital image correlation method

A three-dimensional (3-D) digital image correlation system for deformation measurement in experimental mechanics has been developed. The key technologies applied in the system are discussed in detail, including stereo camera calibration, digital image correlation, 3-D reconstruction, and 3-D displacement/strain computation. A stereo camera self-calibration algorithm based on photogrammetry is proposed. In the algorithm, the interior and exterior orientation parameters of stereo cameras and the 3-D coordinates of calibration target points are estimated together, using the bundle adjustment technique, so the 3-D coordinates of calibration target points are not needed in advance to get a reliable camera calibration result. An efficient image correlation scheme with high precision is developed using the iterative least-squares nonlinear optimization algorithm, and a method based on a seed point is proposed to provide a reliable initial value for the nonlinear optimization. After the 3-D coordinates of the object points are calculated using the triangulation method, the 3-D displacement/strain field could then be obtained from them. After calibration, the system accuracy for static profile, displacement, and strain measurement is evaluated through a series of experiments. The experiment results confirm that the proposed system is accurate and reliable for deformation measurement in experimental mechanics.

Three-dimensional digital image correlation system for deformation measurement in experimental mechanics

In order to improve the prediction capability of spring-back in the computational analysis of sheet metal forming processes, a stress–strain constitutive formulation of non-linear combined hardening rule has been proposed in this paper according to non-linear kinematic hardening theory of Lemaitre and Chaboche and Hill's 1948 anisotropic yielding function. Traditionally, Young's modulus is considered as a constant in engineering application and numerical simulation. In fact, it decreases with plastic deformation. So the effect of the change of Young's modulus with plastic strain on spring-back is considered in the constitutive model. The algorithm of stress update is elastic prediction, plastic correcting and radial returning. Numerical results and experimental results show that the proposed constitutive model significantly improves the prediction accuracy of spring-back.

A constitutive model for spring-back prediction in which the change of Young's modulus with plastic deformation is considered

A digital photogrammetry measurement system (XJTUDP) is developed in this work, based on close range industry. Studies are carried out on key technologies of a photogrammetry measurement system, such as the high accuracy measurement method of a marker point center based on a fitting subpixel edge, coded point design and coded point autodetection, calibration of a digital camera, and automatic image point matching algorithms. The 3-D coordinates of object points are reconstructed using colinear equations, image orientation based on coplanarity equations, direct linear transformation solution, outer polar-line constraints, 3-D reconstruction, and a bundle adjustment solution. Through the use of circular coded points, the newly developed measurement system first locates the positions of the camera automatically. Matching and reconstruction of the uncoded points are resolved using the outer polar-line geometry of multiple positions of the camera. The normal vector of the marker points is used to eliminate the error caused by the thickness of the marker points. XJTUDP and TRITOP systems are tested on the basis of VDI/VDE2634 guidelines, respectively. Results show that their precision is less than 0.1 mm/m. The measurement results of a large-scale waterwheel blade by XJTUDP show that this photogrammetry system can be applied to industrial measurements.

Exploitation of photogrammetry measurement system

In this paper, a new non-contact scheme, based on 3D digital image correlation technology, is presented to measure the full-field wing deformation of in-flight cantilever monoplanes. Because of the special structure of the cantilever wing, two conjugated camera groups, which are rigidly connected and calibrated to an ensemble respectively, are installed onto the vertical fin of the aircraft and record the whole measurement. First, a type of pre-stretched target and speckle pattern are designed to adapt the oblique camera view for accurate detection and correlation. Then, because the measurement cameras are swinging with the aircraft vertical trail all the time, a camera position self-correction method (using control targets sprayed on the back of the aircraft), is designed to orientate all the cameras’ exterior parameters to a unified coordinate system in real time. Besides, for the excessively inclined camera axis and the vertical camera arrangement, a weak correlation between the high position image and low position image occurs. In this paper, a new dual-temporal efficient matching method, combining the principle of seed point spreading, is proposed to achieve the matching of weak correlated images. A novel system is developed and a simulation test in the laboratory was carried out to verify the proposed scheme.

https://iopscience.iop.org/article/10.1088/0957-0233/25/6/065202/pdf

Cheng Guo

Papers

Large deformation measurement scheme for 3D digital image correlation method

Three-dimensional digital image correlation system for deformation measurement in experimental mechanics

A constitutive model for spring-back prediction in which the change of Young's modulus with plastic deformation is considered

Exploitation of photogrammetry measurement system

Full-field wing deformation measurement scheme for in-flight cantilever monoplane based on 3D digital image correlation