> For the complete documentation index, see [llms.txt](https://tlcfem.gitbook.io/suanpan-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://tlcfem.gitbook.io/suanpan-manual/material/material3d/camclay/expcc.md).

# ExpCC

Exponential Hardening Cam-Clay Model

This hardening law is identical to the one documented in ABAQUS manual (4.4.3).

## Hardening

The hardening function is defined as

$$
a=a\_0\exp\left(\left(1+e\_0\right)\dfrac{1-\alpha}{\lambda-\kappa\alpha}\right),
$$

where $$e\_0$$ is the initial void ratio, $$\lambda$$ and $$\kappa$$ are material constants.

If experimental data is available, $$a\_0$$ can be determined as

$$
a\_0=\dfrac{1}{2}\exp\left(\dfrac{e\_1-e\_0-\kappa\ln{}p\_0}{\lambda-\kappa}\right)
$$

where $$p\_0$$ is the initial value of the equivalent pressure stress and $$e\_1$$ is the intercept of the virgin consolidation line with the void ratio axis in a plot of void ratio versus equivalent pressure stress.

## Syntax

```
material ExpCC (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) [11]
# (1) int, unique material tag
# (2) double, elastic modulus
# (3) double, poissons ratio
# (4) double, beta, controls compression side shape
# (5) double, m, slope of CSL
# (6) double, p_t, initial tension strength
# (7) double, a_0, initial a_0
# (8) double, e_0, initial void ratio
# (9) double, lambda
# (10) double, kappa
# [11] double, density, default: 0.0
```

## Usage


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://tlcfem.gitbook.io/suanpan-manual/material/material3d/camclay/expcc.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.