
Choose Tabular to define the amplitude curve as a table of values at convenient points on the time scale. Abaqus interpolates linearly between these values, as needed. For more information, see Defining tabular data.

Choose Equally spaced to give a list of amplitude values at fixed time intervals beginning at a specified value of time. Abaqus interpolates linearly between each time interval. For more information, see Defining equally spaced data.

Choose Periodic to define the amplitude, a, as a Fourier series:
$$\begin{array}{cc}\hfill a& ={A}_{0}+\sum _{n=1}^{N}[{A}_{n}\mathrm{cos}n\omega (t{t}_{0})+{B}_{n}\mathrm{sin}n\omega (t{t}_{0})]\text{for}t\ge {t}_{0},\hfill \\ \hfill a& ={A}_{0}\text{for}t{t}_{0},\hfill \end{array}$$
where ${t}_{0}$, N, $\omega $, ${A}_{0}$, ${A}_{n}$, and ${B}_{n}$, $n=1,2\mathrm{\dots}N$, are userdefined constants. For more information, see Defining periodic data.

Choose Modulated to define the amplitude, a, as
$$\begin{array}{cc}\hfill a& ={A}_{0}+A\mathrm{sin}{\omega}_{1}(t{t}_{0})\mathrm{sin}{\omega}_{2}(t{t}_{0})\text{for}t{t}_{0},\hfill \\ \hfill a& ={A}_{0}\text{for}t\le {t}_{0},\hfill \end{array}$$
where ${A}_{0}$, A, ${t}_{0}$, ${\omega}_{1}$, and ${\omega}_{2}$ are userdefined constants. For more information, see Defining modulated data.

Choose Decay to define the amplitude, a, as
$$\begin{array}{cc}\hfill a& ={A}_{0}+A\mathrm{exp}((t{t}_{0})/{t}_{d})\text{for}t\ge {t}_{0},\hfill \\ \hfill a& ={A}_{0}\text{for}t{t}_{0},\hfill \end{array}$$
where ${A}_{0}$, A, ${t}_{0}$, and ${t}_{d}$ are userdefined constants. For more information, see Defining exponential decay.

Choose Solution dependent to calculate amplitude values based on a solutiondependent variable. For more information, see Defining a solutiondependent amplitude for superplastic forming analysis.

Choose Smooth step to define the amplitude, a, between two consecutive data points $\left({t}_{i},{A}_{i}\right)$ and $\left({t}_{i+1},{A}_{i+1}\right)$ as
$$\begin{array}{cc}\hfill a& ={A}_{i}\mathit{}+\mathit{}({A}_{i+1}{A}_{i}){\xi}^{3}(1015\xi +6{\xi}^{2})\text{for}{t}_{i}\le t\le {t}_{i+1},\hfill \end{array}$$
where $\xi =\left(t{t}_{i}\right)/\left({t}_{i+1}{t}_{i}\right)$. For more information, see Defining smooth step data.

Choose Actuator to import the current value of an actuator amplitude at any given time from a cosimulation with a logical modeling program. For more information, see Defining an actuator amplitude via cosimulation. No additional data is required to define the amplitude curve.

Choose Spectrum to define a spectrum to be used in a response spectrum analysis. For more information, see Specifying a spectrum.

Choose User to define the amplitude curve in user subroutine UAMP (Abaqus/Standard) or VUAMP (Abaqus/Explicit). For more information, see Defining an amplitude via a user subroutine.

Choose PSD definition to define a frequency function that defines the frequency dependence of the random loading in a random response analysis step. This amplitude curve represents the power spectral density function for the random noise source. The PSD amplitude can be referenced in the correlation definition of a base motion boundary condition in a random response step. For more information, see Defining the frequency functions.