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A B S T R A C TThe objective of the final small punch test (SPT) is to determine the fracture properties of materials, such as fracture toughness, when not enough material is available for the conduct of conventional fracture tests. The damage model developed by Gurson, and subsequently modified by Tvergaard and Needleman (GTN), allows for the numerical simulation of the elastic-plastic behaviour until fracture. This model is based on several constitutive material parameters that must be calibrated if the model is to be properly applied. In this paper, we develop a consistent methodology for the identification of the GTN damage parameters based on the adjustment of the load-displacement curve obtained in the SPTs. The methodology presented is applicable to simulating other different SPTs with different thicknesses and test temperatures. Also, the three-dimensional modelling developed will be useful in the future for analysing the possible anisotropy exhibited by some materials. The next step in the simulation will be to determine its validity in other stress fields with different triaxiality ratios, like the one present in CT specimens, the ultimate goal being to allow for the estimation of the material fracture toughness.Keywords damage modelling; Gurson-Tvergaard model; small punch. 0 , b 1 , b 2 , b 11 , b 22 , b 12 = quadratic model constants d = punch diameter (mm) D = diameter of the tensile test specimen (mm) e = specimen thickness (mm) E = Young's modulus (MPa) f = porosity or void volume fraction f * = modified porosity f 0 = initial void volume fraction f c = critical void volume fraction f F = void volume fraction at failure f N = void nucleation volume fraction f * u = constant failure void volume fractioṅ f = void volume fraction incremenṫ f growth = growth void volume fraction incremenṫ f nucleation = nucleation void volume fraction increment g 1 (ε n , f N ) = quadratic model K = strength coefficient m = slope Correspondence: I. I. Cuesta. N O M E N C L A T U R E b

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