LEATHERS

Mechanical Behavior and Energy Response of Leather Materials

An interesting application of VESevo technology is the analysis of the mechanical response of leather materials used in sectors, such as sports and automotive.

A representative use case involves correlating the material’s tensile response with its overall quality, using two key output parameters obtained through non-destructive testing: E’ (storage modulus) and tanδ (loss factor).

The study of different leather samples enables manufacturers and designers to better understand how production methods and surface treatments influence mechanical behavior, supporting the development of more durable and hard-wearing products.

  • To simulate different strain levels, the following setup has been developed.
  • It consists of a vice on which two clamps are mounted. One of the clamp is fixed to the vice while the other one is free to move.
  • Leather specimen is inserted between two clamps as illustrated in the figures on the right side.
  • The moving clamp can be moved by means of a screw that permits to set different strain levels. The imposed strain is calculated by the difference between the final length (after sample is stretched) and initial length, measured by means a calliper:
  • 30 measurements have been acquired for each sample by VESevo device. All tests have been carried out at ambient temperature.

Strain %

LEATHER 1

LEATHER 2

LEATHER 3

LEATHER 4

  • Leather samples have been tested with non-destructive VESevo technology at ambient temperature.
  • To simulate different strain levels, a specific setup has been developed.
  • Storage Modulus and Loss Factor have been used to classify leathers according to their viscoelastic response.

Strain effect on the viscoelastic properties

  • Generally it is possible to see that, for the same leather sample, the Storage Modulus increases as the imposed strain level increases. This is an expected but interesting result since when a strain is imposed the leather becomes much stiffer like he had been subjected to mechanical treatment.
  • For the Loss Factor it is interesting to note that in most cases the 10% applied strain leads to a dramatic decrease in values. This is probably attributable to the capacity of the leather not to deform due to the bending of the leather specimen itself. This could explain this decreasing trend.

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