565 2003 eng 15.1 15.17 15 5 article 1 -- 2003-03-04 -- Since in-depth sensing indentation load–depth data of the entire loading–unloading cycle are available, more information than a single hardness value and an elastic modulus can be extracted from the experimental data. The conventional hardness H (h) = F (h)/Ac(h) and the differential hardness Hd(h)=dF/dAc are calculated as continuous functions of depth h and compared to each other in this paper (F: load, Ac: contact area). It turns out that Hd describes the momentary material resistance to deformation, whereas H integrates over deformation states from first tip–sample contact to current penetration h. This difference is particularly important for materials not homogeneous in depth (e.g. layer systems), and for situations where time-dependent external factors influence the momentary deformation resistance. Photoplasticity is considered as an example for the latter. New Journal of Physics 1367-2630 urn:nbn:de:kobv:526-opus4-5657 B Wolf and A Richter 2003 New J. Phys. 5 15 https://doi.org/10.1088/1367-2630/5/1/315 Creative Commons - CC BY-NC-SA - Namensnennung - Nicht-kommerziell - Weitergabe unter gleichen Bedingungen 3.0 Deutschland Bodo Wolf Asta Richter Physik Fachbereich Ingenieurwesen / Wirtschaftsingenieurwesen (bis 8/2014) open_access Gold Open Access Technische Hochschule Wildau https://opus4.kobv.de/opus4-th-wildau/files/565/The-concept-of-differential-hardness-in-depth-sensing-indentation.pdf