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Synthesize Test Data

Source: R/synthesize_test_data.R
synthesize_test_data.Rd

Synthesize Test Data by Ramberg-Osgood equation.

Usage

synthesize_test_data(
  slope,
  yield.y,
  yield.xp = 0.002,
  ultimate.y,
  ultimate.x,
  offset = 0,
  toe.start.y = 0,
  toe.start.slope = slope,
  toe.end.y = 0,
  enob.x = 14,
  enob.y = 14,
  enob.x_FS = 16,
  enob.y_FS = 16,
  enob.x_noise = 0,
  enob.y_noise = 0,
  x.name = "strain",
  y.name = "stress",
  x.unit = NULL,
  y.unit = "MPa"
)

Arguments

slope

Slope in the linear region.

yield.y

y-value at yield point.

yield.xp

Plastic deformation at yield point. Defaults to 0.002.

ultimate.y

Maximum y-value in the post-linear region.

ultimate.x

Maximum x-value in the post-linear region.

offset

Value of y-offset.

toe.start.y

Intersection of toe-region with y-axis (before adding an offset).

toe.start.slope

Initial slope of toe region.

toe.end.y

End of toe region.

enob.x

Effective number of bits for the synthetic data x-range. Will determine the number of points in the returned data (i.e. 2^enob.x). Also used for adding quantization noise.

enob.y

Effective number of bits for the synthetic data y-range. Used for adding quantization noise.

enob.x_FS

Effective number of bits for the full-scale x-range. Using to determine level of quantization/data-noise in x-values.

enob.y_FS

Effective number of bits for the full-scale y-range. Using to determine level of quantization/data-noise in y-values.

enob.x_noise

Add noise to x-data. Give the effective number of bits for the full-scale x-range.

enob.y_noise

Add noise to y-data. Give the effective number of bits for the full-scale y-range.

x.name

Name for x-values. Defaults to "strain".

y.name

Name for y-values. Defaults to "stress".

x.unit

Unit for x-values. Can be NULL.

y.unit

Unit for y-values. Can be NULL. Defaults to "MPa".

Value

A data.frame with the synthetic data. Units (when provided) are given as variable labels.

Details

Use the Ramberg-Osgood equation in the formulation of Hill to create synthetic data similar to quasi-static mechanical testing. Parameters K and n of the Ramberg-Osgood equation are calculated from the yield-strength (typically at 0.2% offset) and a second point in the post-yield region (e.g. the point of ultimate stress) as proposed by Hill.

Note

As random values are drawn, set a random seed beforehand to get reproducible results.

References

Hill, H. N. (1944). Determination of stress-strain relations from "offset" yield strength values. Aluminum Co of America Pittsburgh Pa.

Ramberg, W., & Osgood, W. R. (1943). Description of Stress-Strain Curves by Three Parameters; National Advisory Committee for Aeronautics Technical Note. NACA-TN-902.

Examples

# Synthesize a test record resembling EN AW-6060-T66
Al_6060_T66 <- synthesize_test_data(
  slope = 69000,
  yield.y = 160,
  ultimate.y = 215,
  ultimate.x = 0.08
)

plot(
  x = Al_6060_T66$strain, y = Al_6060_T66$stress,
  type = "l",
  xlab = "strain", ylab = "stress (in MPa)"
)