Characteristic root of an inhomogeneous truncated shear beam

Returns the eigenvalue an of mode no for a Gazetas & Dakoulas (1985) inhomogeneous truncated shear beam parameterised by inhomogeneity ratio mo and truncation ratio lo. The value is interpolated from the precomputed CylinderRoots table using the requested model (linear glm, non-linear glm, decision tree, or random forest).

Usage

getCylinderRoots(mo, lo, no = 1, model = "nlm", extrapolate = TRUE, OSF = 0.1)

Arguments

mo

Double. Inhomogeneity ratio of the shear-modulus profile. mo = 0 is a homogeneous column. Range 0 to 0.95.

lo

Double. Truncation ratio (top-radius / bottom-radius); lo = 0 is a fully truncated cone. Range 0 to 0.495.

no

Integer. Mode number, 1..8. Default 1 (fundamental).

model

Character. Interpolation model: "lm" (linear GLM), "nlm" (non-linear GLM with interactions, default), "dt" (decision tree), or "rf" (random forest).

extrapolate

Logical. If TRUE (default), allow mo/lo outside the table support and warn; if FALSE, clamp to the table maxima.

OSF

Double. Outlier scale factor used by the random-forest model to shrink the training set around the query point. Default 0.10.

Value

Double. Characteristic root an for the requested mode and parameters.

Examples

getCylinderRoots(mo = 0.45, lo = 0.20, no = 1, model = "nlm")
#> [1] 3.088358