## Definition

The **Dynamic Amplification Factor (DAF)** is also sometimes referred to as the **Dynamic Load Factor (DLF)**. It is defined as the ratio of the displacement obtained when a load is applied dynamically compared to the displacement that would be obtained if the same load was applied statically.

The DAF is a function of the load-time history, and varies depending on the shape of the load pulse, the duration of the pulse *t*_{d} and the natural period of the structure *T*. The following graphs give the value of DAFs for different shapes of load / pressure pulses.

## Triangular Pulses

### Shock Triangular Pulses (*t*_{r} / *t*_{d} = 0.0)

In a shock triangular pulse, the rise time *t*_{r} is 0, i.e. the peak load / pressure is reached instantaneously. As the duration of the pulse increases with respect to the natural period, the DAF increases up to a maximum value of 2.0. Shock triangular pressure pulses are typically encountered in blast detonations.

### Isosceles Triangular Pulses (*t*_{r} / *t*_{d} = 0.5)

In an isosceles triangular pulse, the rise time *t*_{r} is half of the pulse duration *t*_{d}. The maximum value of the DAF for this type of pulse is 1.5, which occurs at a ratio of the pulse duration to the natural period of about 0.9. Isosceles triangular pressure pulses are typically encountered in blast deflagrations.

## Rectangular Pressure Pulses

In a rectangular pressure pulse, the rise time *t*_{r} is 0, i.e. the peak pressure is reached instantaneously. As the duration of the pulse increases with respect to the natural period, the DAF increases up to a maximum value of 2.0. Because the pressure also drops suddenly from its maximum value to zero, the maximum negative DAF that can happen is a minimum value of -2.0.