Seminars

Abstract: In the field of full-field model parameter identification, Integrated Digital Image Correlation (IDIC) was introduced a decade ago as a one-step method to directly correlate digital images by optimizing the parameters of a FEM model of the specimen, making it more accurate than the two-step method of element model updating (FEMU), particularly in challenging test cases (small displacements, complex kinematics, specimen misalignment, image noise). Recently, the IDIC family was extended with correlation of Height profiles instead of Images, named IDHC, while Mechanical Shape Correlation (MSC) was introduced for correlation of the specimen contour for cases where the specimen rotates out of view. In this presentation, I will present the pitfalls, challenges and eventual successful application of IDIC, IDHC, and MSC for (i) mixed-mode interface identification in microelectronics, (ii) correction of SEM imaging artifacts, (iii) absolute cross-grain stress and orientation correlation using EBSD, (iv) time-dependent anelasticity characterization in MEMS microbeams, and (iv) parameter identification of micron-sized freestanding stretchable electronic interconnects.

Bio: Johan Hoefnagels obtained his MSc and PhD in Applied Physics at TU/e, with a PhD thesis on advanced optical diagnostics of surface processes during thin film deposition. After his PhD he made a dramatic switch to become assistant professor in ‘experimental micromechanics’ at the department of mechanical engineering, where he later became associate professor in the same field. He leads the ‘Multi-Scale lab’ dedicated to ‘integrated mechanical testing’, which is one of TU/e’s 10 strategic labs. Till 2018, Johan has (co-)authored >80 journal publications (of which ~50 times as corresponding author) and >100 refereed proceedings/book contributions. At international conferences, has given >100 presentations, of which around a third on invitation, and organized over 10 symposia. He has over two years of international research experience, built up during international visits to, amongst others, IMEC (Leuven, Belgium), SUNY (Albany, USA), NIST (Gaithersburg, USA), CSM (Golden, USA), and Harvard University (Cambridge, USA). He is Editor-in-Chief of scientific Journal Strain (impact factor 2.2) and Dutch representative of the European Structural Integrity Society (ESIS).