Q2. What are the future works in "An experimental and numerical study on the volume change of particle- lled elastomers in various loading modes" ?
However, further studies on the e ect of particle geometry, size distribution, and interaction e ects should be carried out before de nitive conclusions can be drawn.
Q3. How was the model exposed to UT loading?
The model was exposed to UT loading by applying the stress - time data obtained in the experimental tests to the upper boundary as a negative pressure force, while the vertical external boundary was free to move horizontally.
Q4. What was the effect of deforming the specimens?
For the in situ tension images, it was found that deforming the specimens changed the conductive properties of the compounds, reducing the image quality at large deformations.
Q5. What was the accessible method for measuring global volume changes?
For the early research on the volumetric behaviour of elastomers, the most accessible method for measuring global volume changes accompanying deformation was through dilatometry tests [16, 17, 18, 19].
Q6. How many images were obtained of the surface at the centre and the edge of the specimen?
Prior to any deformation, images at 60, 100 and 300 times magni cation were obtained of the surface at both the centre and the edge of the specimen, resulting in six images for each compound.
Q7. How large was the largest particle found in the inspected regions?
The largest particle found in the inspected regions had a projected area of 1125 m2, found at the edge of the FKM material, while the smallest particle possible to identify with this method at 60 magni cation had a projectedarea of 0.09 m2.
Q8. What was used to capture the images of the specimens?
For this purpose, a grey scale speckle pattern was applied to the specimens prior to testing, and two Prosilica GC2450 CCD cameras were used to capture frames of the wide and narrow surface of the specimen throughout the tests.
Q9. What are the main advantages of llers?
These llers improve mechanical properties like sti ness and strength, but may also alter the volumetric behaviour of the compounds.
Q10. What is the main purpose of unit cell simulations?
Unit cell simulations are often used to explain globally observed results by studying mechanisms occurring at the scale of the material constituents.
Q11. Why is the fraction of internal voids limited?
the fraction of internal voids is expected to be limited, due to the sti and elastic volume response observed in the CAC experiments.
Q12. What is the stress needed to separate the two surfaces?
The stress needed to separate the two surfaces increases linearly with a sti ness k until an initiation stress Tini is reached (coinciding with the initiation deformation ini).
Q13. How did Le Cam and Toussaint measure the volume change of a natural rubber?
Using DIC, Le Cam and Toussaint [20] looked at the competition between volume increase due to void growth and volume decrease due to crystallization in natural rubber loaded in tension.
Q14. Why were the parameters of the base model set to be k = 6 GPa/?
Due to the absolute lack of experimental data on the matrix-particle interface behaviour of the materials, the parameters of the base model were set to be Tini = 6 MPa, k = 6 GPa/ m, and Gc = 15 J/m 2, as this gave a reasonable representation of the experimental results.
Q15. What are the main reasons for the lack of particle interaction in the model?
as already mentioned, the model is too simple to provide quantitatively precise results due to the lack of matrix cavitation, neglecting the particle size distribution, inaccurate modelling of the complex particle geometries, and the lack of particle interaction e ects.
Q16. What is the volumetric behaviour of the elastomer?
Some implications of this loading mode dependent volume behaviour for the constitutive modelling of particle- lled elastomers are discussed in the following section.