# Dhakal

Dhakal Degradation

## References

1. [10.1061/(ASCE)0733-9445(2002)128:9(1139)](https://doi.org/10.1061/\(ASCE\)0733-9445\(2002\)128:9\(1139\))

## Syntax

```
material Dhakal (1) (2) (3) (4)
# (1) int, unique material tag
# (2) int, host material tag
# (3) double, yield strain
# (4) double, geometry parameter
```

## Theory

The model is proposed for modelling buckling of reinforcement bars in concrete members.

The geometry parameter `[4]` is defined as

$$
\sqrt{\dfrac{f\_y}{100\~\text{MPa}}}\dfrac{L}{D}.
$$

Since this parameter is calibrated according to dimensional constant $$100\~\text{MPa}$$, the whole analysis must then use the same unit system.

This is a common issue in lots of phenomenological models, which lack a clear implication of those ad-hoc parameters.

## Example

```
material MPF 1 2E5 400 .01
material Dhakal 2 1 5E-3 50
materialTest1D 2 -4E-4 10 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 100
```

![example](https://4006314410-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MQ5rMqEBbzA9NgGETGX%2Fuploads%2Fgit-blob-4fb086f1149787f2f750d6778dce476132adc12c%2FDhakal.EX1.svg?alt=media)