Powder test storage modulus

What is storage modulus?

The storage modulus, either E’ or G’, is the measure of the sample’s elastic behavior. The ratio of the loss to the storage is the tan delta and is often called damping. It is a measure of the energy dissipation of a material. Figure 2.

How does a powder resistance test work?

The test measures resistance of a powder sample as controlled flow is imposed at different speeds. Powders that flow freely will transfer very little resistance through the powder column in either a downward or an upward direction. Conversely, poorly flowing powders exhibit substantial amounts of force in either direction. Measured Parameters

How do you test powder flow stability?

An evaluation of the flow stability of the powder is also made by comparing the work needed to move the blade though the powder at the start of the test compared to the work required to move the powder at the same speed at the end of the test. The powder flow speed dependency (PFSD) test provides 5 sets of 2 cycles at increasing speeds.

How does a powder test work?

The downward parts of the cycles compact the powder and the upward stroke of the cycle uses a lifting action. The test measures resistance of a powder sample as controlled flow is imposed at different speeds. Powders that flow freely will transfer very little resistance through the powder column in either a downward or an upward direction.

How is a powder's tap density determined?

It is determined by measuring the mass of a powder sample after it has been subjected to a specific number of taps or vibrations. The powder's tap density is influenced by particle size, shape, surface area, and interparticle forces. Tap density is determined as the powder mass per volume unit (g/cm3).

What is the modulus of a sinusoidal force?

Because we are applying a sinusoidal force, we can express the modulus as an in-phase component, the storage modulus, and an out of phase component, the loss modulus, see Figure 2. The storage modulus, either E’ or G’, is the measure of the sample’s elastic behavior. The ratio of the loss to the storage is the tan delta and is often called damping.