> 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/guide/metal.md).

# Metal

To model metals, von Mises yielding criterion based models are often used.

## 1D

The simplest von Mises bilinear hardening model with/without linear kinematic hardening rule (Prager's rule) can be used for simple analysis tasks.

The [`Bilinear1D`](/suanpan-manual/material/material1d/vonmises/bilinear1d.md) model supports both linear isotropic and kinematic hardening rules. The [`BilinearMises1D`](/suanpan-manual/material/material1d/vonmises/bilinearmises1d.md) model is an example of derived classes of the `Mises1D` model and only implements the isotropic hardening.

The [`ExpMises1D`](/suanpan-manual/material/material1d/vonmises/expmises1d.md) model implements the exponential type isotropic hardening rule with a saturated stress, again there is no kinematic hardening defined.

For nonlinear kinematic hardening rule, often an Armstrong-Frederick type definition is used for modelling Bauschinger effect. Two models are available, they are the [`ArmstrongFredick1D`](/suanpan-manual/material/material1d/vonmises/armstrongfrederick1d.md) model which is rate dependent and the [`VAFCRP1D`](/suanpan-manual/material/material1d/vonmises/vafcrp1d.md) model which is rate dependent, the corresponding viscosity is defined in a Peric style. If experiment data is available, those two models will give better simulation results for a wide range of metals.

Another model that can be used is the asymmetric [`SteelBRB`](/suanpan-manual/material/material1d/hysteresis/steelbrb.md) model which is developed to simulate BRBs. It has a rheology model which reveals some insights of response.

For general phenomenological hysteresis models, the [`MPF`](/suanpan-manual/material/material1d/hysteresis/mpf.md) model ( Menegotto-Pinto-Filippou model) and the [`RambergOsgood`](/suanpan-manual/material/material1d/hysteresis/rambergosgood.md) model are widely used. In terms of the determination of the model parameters, readers are referred to the related literature.

The Bouc-Wen family ([`BoucWen`](/suanpan-manual/material/material1d/hysteresis/boucwen.md) and [`BWBN`](/suanpan-manual/material/material1d/hysteresis/bwbn.md)) can be used.

## 3D

Apart from the [`MPF`](/suanpan-manual/material/material1d/hysteresis/mpf.md) model and the [`RambergOsgood`](/suanpan-manual/material/material1d/hysteresis/rambergosgood.md) model, other models have the corresponding 3D versions.


---

# 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/guide/metal.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.