{"id":674,"date":"2020-10-08T13:38:25","date_gmt":"2020-10-08T18:38:25","guid":{"rendered":"https:\/\/www.mse.iastate.edu\/sidpathak\/?page_id=674"},"modified":"2020-10-08T16:31:26","modified_gmt":"2020-10-08T21:31:26","slug":"nanoindentation","status":"publish","type":"page","link":"https:\/\/www.mse.iastate.edu\/sidpathak\/nanoindentation\/","title":{"rendered":"Nanoindentation"},"content":{"rendered":"<ul style=\"list-style-type: square\">\n<li>\n<h4><span style=\"color: #ff0000\"><a style=\"color: #ff0000\" href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0927796X15000157\" target=\"_blank\" rel=\"noopener noreferrer\">Spherical Nanoindentation Stress-Strain analysis<\/a><\/span><\/h4>\n<table style=\"border-collapse: collapse;width: 100%\">\n<tbody>\n<tr>\n<td style=\"width: 51.1829%\">We have pioneered the development of novel data-analysis protocols for spherical nanoindentation which allow meaningful indentation stress-strain curves to be extracted from the raw datasets. <span style=\"color: #ff0000\"><a style=\"color: #ff0000\" href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0927796X15000157\" target=\"_blank\" rel=\"noopener noreferrer\">Read more about the analysis<\/a><\/span><\/p>\n<h4><\/h4>\n<h4>Hertz Principle<\/h4>\n<p>Assumptions: Linear elastic, isotropic material response, frictionless contact<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-722 img-responsive\" src=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/1.png\" alt=\"\" width=\"514\" height=\"90\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>where a is the radius of the contact boundary at the indentation load P, and he is the elastic indentation depth. Reff and Eeff are the effective radii and effective modulus of the indenter and the specimen system respectively.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-725 img-responsive\" src=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/2.png\" alt=\"\" width=\"467\" height=\"82\" srcset=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/2.png 530w, https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/2-300x53.png 300w\" sizes=\"auto, (max-width: 467px) 100vw, 467px\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>where \u03b3 and E are the Poisson\u2019s ratio and Young\u2019s modulus and subscript s and i refer to the specimen and the indenter, respectively.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-727 img-responsive\" src=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/3.png\" alt=\"\" width=\"220\" height=\"60\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>where P \u0303, h \u0303e, and S are the measured load signal, the measured displacement signal, and the continuous stiffness measurement signal in the initial loading segment from the machine, respectively. P* and h* are the values of load and displacement signals at the point of effective contact.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-728 img-responsive\" src=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/4.png\" alt=\"\" width=\"119\" height=\"68\" srcset=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/4.png 153w, https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/4-150x87.png 150w\" sizes=\"auto, (max-width: 119px) 100vw, 119px\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Indentation stress<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-729 img-responsive\" src=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/5.png\" alt=\"\" width=\"125\" height=\"58\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>indentation strain<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-730 img-responsive\" src=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/6.png\" alt=\"\" width=\"132\" height=\"61\" \/><\/p>\n<p>&nbsp;<\/td>\n<td style=\"width: 48.8171%\">&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-695 img-responsive alignnone\" src=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/Sph-nano-indentation.png\" alt=\"\" width=\"1160\" height=\"1473\" srcset=\"https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/Sph-nano-indentation.png 1160w, https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/Sph-nano-indentation-236x300.png 236w, https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/Sph-nano-indentation-806x1024.png 806w, https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/Sph-nano-indentation-768x975.png 768w, https:\/\/www.mse.iastate.edu\/sidpathak\/files\/2020\/10\/Sph-nano-indentation-378x480.png 378w\" sizes=\"auto, (max-width: 1160px) 100vw, 1160px\" \/><\/p>\n<table style=\"height: 72px;width: 100%;border-collapse: collapse;border-style: hidden\">\n<tbody>\n<tr style=\"height: 72px\">\n<td style=\"width: 100%;height: 72px\">Fig. (a) Schematic of the indentation zone in the spherical indentation. (b) Schematic of a typical measured spherical indentation load-displacement curve with the initial and final contact geometries.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span style=\"font-size: 8pt;color: #000000\"><a style=\"color: #000000\" href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0927796X15000157\" target=\"_blank\" rel=\"noopener noreferrer\">ref. Pathak, S., &amp; Kalidindi, S. R. (2015). Spherical nanoindentation stress-strain curves. <i>Materials science and engineering: R: Reports<\/i>,\u00a0<i>91<\/i>, 1-36.<\/a><\/span><\/p>\n<p>&nbsp;<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Spherical Nanoindentation Stress-Strain analysis We have pioneered the development of novel data-analysis protocols for spherical nanoindentation which allow meaningful indentation stress-strain curves to be extracted from the raw datasets. Read more about the analysis Hertz Principle Assumptions: Linear elastic, isotropic material response, frictionless contact &nbsp; &nbsp; &nbsp; &nbsp; where a is the radius of the &hellip; <a href=\"https:\/\/www.mse.iastate.edu\/sidpathak\/nanoindentation\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Nanoindentation<\/span><\/a><\/p>\n","protected":false},"author":2625,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-674","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.mse.iastate.edu\/sidpathak\/wp-json\/wp\/v2\/pages\/674","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mse.iastate.edu\/sidpathak\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.mse.iastate.edu\/sidpathak\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.mse.iastate.edu\/sidpathak\/wp-json\/wp\/v2\/users\/2625"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mse.iastate.edu\/sidpathak\/wp-json\/wp\/v2\/comments?post=674"}],"version-history":[{"count":23,"href":"https:\/\/www.mse.iastate.edu\/sidpathak\/wp-json\/wp\/v2\/pages\/674\/revisions"}],"predecessor-version":[{"id":739,"href":"https:\/\/www.mse.iastate.edu\/sidpathak\/wp-json\/wp\/v2\/pages\/674\/revisions\/739"}],"wp:attachment":[{"href":"https:\/\/www.mse.iastate.edu\/sidpathak\/wp-json\/wp\/v2\/media?parent=674"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}