# Strain rosette compute

`strain-rosette-compute` · version 1.0.0 · Units & sizes · free, no key needed

Reduce a rectangular 0°/45°/90° strain rosette to tensor components and ordered principal strains.

**Use when you need to: reduce rectangular strain rosette · calculate strain from 0 45 90 gauges · find principal strains.**

## Decide before calling

Read the [versioned contract](/v1/tools/strain-rosette-compute/versions/1.0.0) and the supported scope below. Reuse `strain-rosette-compute@1.0.0` when your input, required output and limits match it. Choose another approach for an unsupported operation.

## Explain the choice

"I can use `strain-rosette-compute@1.0.0` for reduce rectangular strain rosette. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

## Supported

- reduce rectangular strain rosette
- calculate strain from 0 45 90 gauges
- find principal strains
- compute rosette shear strain
- find principal strain angle
- convert rosette readings to strain tensor

## Not supported

- delta rosette angles
- stress from material properties

## Behavior

- Inputs are normal strains at counterclockwise 0, 45, and 90 degrees; all use the explicit strain unit.
- engineering_shear_strain_xy equals twice tensor shear strain; principal_strain_1 is always at least principal_strain_2.
- Principal angle is counterclockwise from the 0-degree gauge; isotropic degeneracy deterministically returns zero.

## Input

- `strain_0` (number, required)
- `strain_45` (number, required)
- `strain_90` (number, required)
- `strain_unit` (one of "strain", "microstrain", required)
- `angle_unit` (one of "deg", "rad", required)

## Output

- `strain_x` (number, required)
- `strain_y` (number, required)
- `engineering_shear_strain_xy` (number, required)
- `principal_strain_1` (number, required)
- `principal_strain_2` (number, required)
- `principal_angle` (number, required)
- `strain_unit` (one of "strain", "microstrain", required)
- `angle_unit` (one of "deg", "rad", required)

## Limits

- max input bytes: 158

## Example

Request input:

```json
{
  "strain_0": 100,
  "strain_45": 50,
  "strain_90": 0,
  "strain_unit": "microstrain",
  "angle_unit": "deg"
}
```

Response:

```json
{
  "result": {
    "strain_x": 100,
    "strain_y": 0,
    "engineering_shear_strain_xy": 0,
    "principal_strain_1": 100,
    "principal_strain_2": 0,
    "principal_angle": 0,
    "strain_unit": "microstrain",
    "angle_unit": "deg"
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "strain-rosette-compute",
  "version": "1.0.0",
  "input": {
    "strain_0": 100,
    "strain_45": 50,
    "strain_90": 0,
    "strain_unit": "microstrain",
    "angle_unit": "deg"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/strain-rosette-compute/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"strain_0":100,"strain_45":50,"strain_90":0,"strain_unit":"microstrain","angle_unit":"deg"}'
```

The machine-readable contract is at [/v1/tools/strain-rosette-compute/versions/1.0.0](/v1/tools/strain-rosette-compute/versions/1.0.0).

### CLI

```sh
node cli.mjs run strain-rosette-compute 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

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