Effect of confinement level on mechanical behaviour using the small punch test

• Mechanical properties depending on the level of confinement have been studied.
• Dog bone shaped miniature specimens have been used.
• A correlation between tensile tests and small punch tests has been established.

Nowadays, the small punch test is used successfully to characterize the mechanical behaviour of materials especially in those cases in which an insufficient amount of material is available to carry out standard tests. This test basically consists of deforming a miniature specimen whose edges are firmly gripped by a die. But, what happens if the level of confinement varies? This paper analyses the effect of varying the degree of confinement of an SPT specimen on its mechanical behaviour. This variation is achieved by modifying the geometry of the specimen from a conventional square shape to a dog bone shape, maintaining the same thickness as usual. With these specimens, confinement variations, ranging from the typical biaxial confinement (conventional SPT specimens) to an almost uniaxial confinement, as well as three intermediate values in between, have been achieved. The results obtained enable the establishment of a variation of mechanical properties depending on the level of confinement of each miniature specimen.

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