TABLE 5.

Experimental mean surface displacements (Figure 5) for all measurement regions with mean indentation forces ${\mathit{f}}^{*}=\mathit{f}\left({\mathit{\delta }}_{\mathit{I}}\right)$ (Table 4) at the discrete indentation depths ${\mathit{\delta }}_{\mathit{I}}$ as reference parameters for the inverse FE analysis. Each polynomial curve fit u(x) is defined for ${\mathit{x}}_{\mathit{min}}\le \mathit{x}\le {\mathit{x}}_{\mathit{max}}$ (Figure 5D) for an inverted z-axis. ${\mathit{x}}_{\mathit{min}}$ and ${\mathit{x}}_{\mathit{max}}$ are the intersection points with the indenter tip and the reference plane (δ = 0), respectively. A visualization of all displacements can be found in Supplementary Material S4.

Measurement region	${\mathit{\delta }}_I$ for I = 1, 2, 3, 4 in mm	$f^{*}$ in N	Polynomial curve fit u(x)
			Range limits in mm		Coefficients u n
			$x_{min}$	$x_{max}$	u 1	u 2	u 3	u 4
R1	5	1.45	6.089	42.859	−1.065e-04	6.927e-03	−3.190e-02	−2.971
	10	3.33	7.831	53.080	−4.762e-05	3.425e-03	8.567e-02	−7.078
	15	5.65	8.837	62.945	−4.873e-05	4.178e-03	1.030e-01	−10.89
	20	8.40	9.671	66.729	−6.188e-05	5.926e-03	8.836e-02	−13.9
R2	6.25	1.51	7.342	37.005	−1.993e-04	1.256e-02	−1.166e-01	−2.782
	12.5	5.53	8.943	45.946	−1.246e-04	8.224e-03	6.108e-02	−8.087
	18.75	6.27	9.756	57.187	−5.454e-05	3.227e-03	2.287e-01	−13.43
	25	9.86	10.000	65.213	−5.666e-05	4.188e-03	2.368e-01	−17.54
R3	6.25	1.12	7.566	35.484	−2.180e-04	1.351e-02	−1.365e-01	−2.433
	12.5	2.92	9.293	42.561	−1.745e-04	1.119e-02	5.990e-03	−7.075
	18.75	5.39	9.942	52.568	−6.188e-05	3.089e-03	2.467e-01	−12.52
	25	8.53	10.000	60.609	−6.175e-05	4.191e-03	2.418e-01	−16.31
R4	6.25	1.37	7.348	36.761	−1.688e-04	1.022e-02	−6.487e-02	−3.037
	12.5	3.15	9.026	49.639	−3.117e-05	3.522e-04	2.401e-01	−8.972
	18.75	5.34	9.831	61.055	−1.742e-05	−5.439e-04	3.221e-01	−13.67
	25	7.94	10.000	67.845	−1.813e-05	−4.167e-04	3.827e-01	−18.39
R5	6.25	1.28	7.331	39.196	−1.194e-04	7.065e-03	−8.779e-03	−3.318
	12.5	3.21	8.955	43.200	−1.068e-04	5.409e-03	1.698e-01	−8.818
	18.75	6.34	9.697	52.244	−4.996e-05	1.204e-03	3.545e-01	−14.68
	25	11.41	9.990	61.790	−5.988e-05	3.226e-03	3.379e-01	−19.07
R6	4	1.81	6.811	43.314	6.69e-07	−4.281e-04	5.611e-02	−1.682
	8	5.25	8.518	45.484	−4.42e-05	2.257e-03	7.747e-02	−4.033
	12	11.10	9.272	51.617	2.646e-07	−2.121e-03	2.639e-01	−8.007
	16	19.96	9.865	57.954	8.678e-06	−3.241e-03	3.435e-01	−10.71
A1	4	1.98	6.425	45.758	−7.288e-06	1.786e-04	5.058e-02	−1.99
	8	5.06	8.082	45.302	−6.09e-05	3.765e-03	5.473e-02	−4.543
	12	9.24	8.921	49.949	−8.825e-05	6.103e-03	6.618e-02	−3.34
	16	14.54	9.463	55.936	−5.966e-05	4.297e-03	1.412e-01	−10.9
A2	5	3.52	7.095	46.183	−1.724e-05	5.926e-04	6.401e-02	−2.522
	10	9.04	8.513	50.939	−3.94e-05	2.501e-03	9.710e-02	−6.23
	15	15.84	9.315	57.370	−4.751e-05	3.453e-03	1.354e-01	−10.16
	20	23.02	9.878	65.679	−3.791e-05	2.684e-03	1.961e-01	−13.72
A3	5	2.19	7.553	39.789	1.582e-06	−3.823e-04	6.318e-02	−2.008
	10	6.77	9.309	47.862	−2.645e-05	1.298e-03	9.510e-02	−4.625
	15	13.42	9.795	56.835	−2.952e-05	1.614e-03	1.561e-01	−8.663
	20	20.12	10.000	65.710	−2.59e-05	1.704e-03	1.772e-01	−11.65
A4	5	2.74	7.252	49.359	5.653e-06	−9.252e-04	8.103e-02	−2.425
	10	6.66	8.761	49.564	−8.992e-06	−9.275e-04	1.988e-01	−6.479
	15	11.44	9.584	57.680	−7.473e-06	−1.211e-03	2.744e-01	−10.36
	20	16.80	9.981	63.514	−1.605e-05	−1.236e-04	2.837e-01	−13.41
A5	5	2.25	6.772	47.663	7.959e-06	−1.075e-03	9.514e-02	−2.954
	10	5.93	8.856	53.956	2.45e-05	−3.237e-03	2.213e-01	−6.363
	15	11.04	9.616	54.403	1.31e-05	−3.276e-03	3.356e-01	−10.67
	20	17.59	9.969	59.772	7.236e-06	−3.051e-03	3.979e-01	−14.43
A6	3.25	5.97	6.440	52.595	1.001e-05	−9.623e-04	4.477e-02	−1.149
	6.5	17.97	8.652	54.386	3.466e-05	−3.406e-03	1.263e-01	−2.373
	9.75	33.95	9.422	61.089	3.14e-05	−3.384e-03	1.605e-01	−4.337
	13	51.03	9.817	67.835	3.628e-05	−4.454e-03	2.358e-01	−6.824