Doctor Erwin Hack

Doctor Erwin Hack

Dr. Erwin Hack

Empa - Swiss Federal Laboratories for Materials Science and Technology Transport at Nanoscale Interfaces

Email:, Tel: +41 58 765 42 73



Erwin Hack holds a diploma in theoretical physics and a PhD in physical chemistry, both from the University of Zurich, Switzerland. He is senior scientist at Empa, the Swiss Federal Laboratories for Materials Science and Technology, and member of its Research Commission. His research interest is in full-field optical measurement techniques including THz imaging, digital speckle pattern interferometry and thermography. He coordinated a European FP7 research project on the validation of dynamic models using integrated simulation and experimentation (ADVISE) and is partner in national and international research projects on validation and optical full-field techniques. Erwin authored or co-authored more than 120 papers in peer-reviewed journals and conferences and co-edited two books. He is lecturer at ETH Zurich, Associate Editor of “Optics and Lasers in Engineering”, vice-chair of CEN WS71 on “Validation of computational solid mechanics models” and vice-president of the „Swiss Society for Non-destructive Testing.

MBL meets OPTIMESS 2019 lecture:

"Optical measurement techniques"

Camera based optical measurement systems such as Digital Image Correlation (DIC) are increasingly used in industrial environments to validate model simulations. Although DIC is a well-established technique for measuring displacement and strain fields, the estimation of its measurement uncertainty in an industrial environment is still being discussed. The calibration uncertainty for the DIC system represents the minimum achievable measurement uncertainty in a validation experiment, and a methodology for estimating the measurement uncertainty in a validation experiment will be discussed.

A recent guideline published by CEN details the comparison of simulation data with data from full-field measurements for the purpose of validating the numerical model. The guideline recommends the use of full-field data, e.g. obtained from calibrated DIC systems, and the application of image decomposition. While an inter-laboratory study demonstrated its usefulness in a laboratory environment on different representative test objects, the methodology is now being deployed in an advanced structural test in an industrial environment.

We will present a step-by-step procedure to the validation process in an industrial environment based on a novel flowchart with a focus on the data generation from experiment and simulation. We will present a novel flowchart for validation and relate it to the recommendations of the ASME V&V and CEN guidelines. Difficulties in the practical applicability, such as complex geometry, or lack of numerical or experimental data points (e.g. due to optical inaccessibility, or element erosion in damaged areas of the FE models) and their mitigation will be addressed.