An apparatus is described which permits the measurement of the modulus and yield strength of gels. The device consists of a cylindrical cell with internal fins to prevent slip of the gel at the cell walls. Pressure is applied to the cell and the volume of displaced gel is measured. A numerical finite-element simulation of gel deformation yields a proportionality constant relating pressure and displaced volume. The simulation has been run for a wide range of geometries. Model polyacrylamide gels were made having moduli from 1,500 to 9,620 Pa as measured by a rheometer. The moduli values calculated from the test cell data using the finite-element simulation were on average 6.1% lower than the values measured by the rheometer. The adaptation of the cell to measuring gel properties at elevated temperatures and pressures is discussed.
All Science Journal Classification (ASJC) codes
- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering