osis-python 0.3.8

A Python client library for Osis APDL

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pyosis

Python client library for OSIS Bridge & Tunnel Analysis Platform (developed by CCCC Highway Consultants Co., Ltd.).

pyosis provides an object-oriented Python API for automating the creation of bridge/tunnel finite element models, executing analysis solvers, and extracting post-processing results.

Installation

Due to naming conflicts on PyPI, please install using:

pip install osis-python

If your mirror hasn't synced yet, use:

pip install osis-python -i https://pypi.org/simple

Requirements

• OSIS >= 5.0 (includes the required Python runtime environment)
• Python >= 3.8

Quick Start

1. Using OSISEngine (Recommended)

OSISEngine is the core facade class of pyosis, integrating all module managers and providing a unified project-level entry point:

from pyosis.core.engine import OSISEngine

engine = OSISEngine()

# Clear project
engine.clear()

# Set global parameters
engine.control.set_gravity_acceleration(9.8066)
engine.control.set_calc_tendon(True)
engine.control.set_calc_creep(True)

# Create sections
sec = engine.section.create_circle("Circle Section", d=0.5, tw=0.02)

# Create materials
mat = engine.material.create_conc("C30 Concrete", eCode="JTG3362_2018", eGrade="C30")

# Create nodes
n1 = engine.node.create(0, 0, 0)
n2 = engine.node.create(15, 0, 0)

# Create elements
elem = engine.element.create_beam3d(
    n1.no, n2.no, nMat=mat.no, nSec1=sec.no, nSec2=sec.no
)

# Create boundaries
bd = engine.boundary.create_general(bX=1, bY=1, bZ=1, bRX=1, bRY=1, bRZ=1)
bd.assign("a", [n1.no])

# Create load case and add loads
lc = engine.load.create("Self-weight", load_case_type="D")
lc.create_gravity()

# Solve
engine.solve()

2. Engine Convenience Methods

OSISEngine provides project-level convenience methods:

# Project management
engine.new_project()           # Create new project
engine.save_project()          # Save current project
engine.open_project(path)      # Open existing project

# Model information
summary = engine.model_summary()  # Returns dict with all manager counts

# Import/Export
engine.export_apdl(path)       # Export to APDL format
engine.import_apdl(path)       # Import from APDL format

# Result output for calculation book
engine.output_result_for_calc_book()

# Matrix output
engine.matrix("matrix_1", [[1, 2],[3, 4]])

3. Using Managers Directly

If you don't need the convenience methods of Engine, you can also import individual managers directly:

from pyosis.material import material_manager
from pyosis.node import node_manager

mat = material_manager.create_conc("C30", eCode="JTG3362_2018", eGrade="C30")
node = node_manager.create(0, 0, 0)

Core Architecture

Manager System

pyosis adopts a Manager pattern to organize code. Each module corresponds to a Manager:

Manager	Attribute	Description
MaterialManager	engine.material	Materials (concrete, steel, prestressed, rebar, etc.)
SectionManager	engine.section	Sections (box girder, T-girder, hollow slab, steel box, etc.)
NodeManager	engine.node	Nodes
ElementManager	engine.element	Elements (beam, truss, spring, cable, shell)
BoundaryManager	engine.boundary	Boundaries (general support, master-slave, elastic support, etc.)
GeometryManager	engine.geometry	Geometric entities (splines, spatial curves)
PropertyManager	engine.prop	Properties (coordinate systems, creep/shrinkage, damping, P-U curves, element thickness assignments)
ThicknessManager	engine.thickness	Shell thickness properties
LoadCaseManager	engine.load	Load cases
StageManager	engine.stage	Construction stages
TendonManager	engine.tendon	Tendons (properties + shapes)
LiveManager	engine.live	Live loads (grades + lanes + cases)
SettlementManager	engine.settlement	Settlement analysis
StabilityManager	engine.stability	Stability analysis
DynamicManager	engine.dynamic	Dynamic analysis
PostManager	engine.post	Post-processing (load combinations, design checks)
ResultManager	engine.result	Result export (load case / envelope / check results)
ControlManager	engine.control	Global control parameters
ProjectManager	engine.project	Project operations

Sub-Managers

Some managers contain sub-managers, accessed via attributes:

# Element groups
grp = engine.element.group.create("Main Girder Elements")
grp.add([1, 2, 3])

# Boundary groups
bg = engine.boundary.group.create("Abutment Boundaries")
bg.add([1, 2])

# Various boundary types
engine.boundary.create_general(bX=1, bY=1, bZ=1, bRX=1, bRY=1, bRZ=1)  # General support
engine.boundary.create_master_slave(nMast=1, nSlav=2, dDir=1)           # Master-slave
engine.boundary.create_release(nElem=1, iReleaseEnd=2)                  # End release
engine.boundary.create_elstcspt(nNode=1, dK=[1e9, 1e9, 1e9, 0, 0, 0])  # Elastic support
engine.boundary.create_general_elstcspt(nNode=1, bX=1, bY=1, bZ=1, dKx=1e9, dKy=1e9, dKz=1e9)  # General elastic
engine.boundary.create_rigid(nNode1=1, nNode2=2)                        # Rigid link
engine.boundary.create_section_factor(nElem=1, iEnd=1)                  # Section factor

# Tendons
prop = engine.tendon.prop.create_in(
    "15-10", mat_no=1, e_code="GBT5224_2014",
    diameter=15.2, n_num=10, d_pipe=0.09
)
shape = engine.tendon.shape.create_arc3d(
    "N1", n_num=2, prop="15-10",
    element_group="Main Girder Elements", curve_name="curve1"
)

# Live loads
grade = engine.live.grade.create("Highway-Class I")
lane = engine.live.lane.create("Lane 1")
case = engine.live.case.create("Live Load Case 1")

Property & Thickness Management

# Coordinate systems
engine.prop.coord.create_local("CS1", origin=[0, 0, 0], x_axis=[1, 0, 0], y_axis=[0, 1, 0])

# Creep and shrinkage
engine.prop.creep_shrink.create("Creep1", eCode="JTG3362_2018", eGrade="C30")

# Damping
engine.prop.damping.create("Damping1", dDmp=0.05)

# P-U curve (for soil-structure interaction)
engine.prop.pu_curve.create("PU1", data=[(0, 0), (0.01, 1000), (0.02, 1500)])

# Element thickness assignment
engine.prop.thickness.assign_element(nElem=1, dThick=0.3)

# Shell thickness properties
engine.thickness.create_uniform("Thick1", dThick=0.3)
engine.thickness.create_tapered("Thick2", dThick1=0.2, dThick2=0.4)

Geometry Queries

The GeometryManager supports querying geometric entities:

# Get all splines
splines = engine.geometry.all("spline")

# Get a specific spline
spline = engine.geometry.get("spline", name="curve1")

# Filter by type
arcs = engine.geometry.filter("spline", spline_type="ARC3D")

Data Class Objects

Create and query operations return data class objects (dataclass) instead of raw dictionaries:

elem = engine.element.get(1)
print(elem.no)          # ID
print(elem.node_vec)    # Node list
print(elem.mat)         # Material ID

# Objects support operations (operations下沉 to object)
lc = engine.load.get("Self-weight")
lc.create_gravity()
lc.create_nforce(1, dFx=1000)

Explicit Numbering

Some create_* functions support explicit numbering via the no parameter. If not specified, the number is automatically assigned:

# Auto-assigned number
sec = engine.section.create_circle("Section 1", d=0.5)

# Explicit number
sec = engine.section.create_circle("Section 1", d=0.5, no=100)

Result Export

After solving, you can export various analysis results using engine.result. All export methods return pandas DataFrames:

# Export load case results (element forces)
df = engine.result.loadcase("Self-weight", "LCEF")

# Export envelope results (element forces)
df = engine.result.env("Basic Combination Envelope", "EnvEF")

# Export design check results
df = engine.result.check(
    "混凝土", "正截面抗弯验算", "Basic Combination"
)

# Batch export all check results from Check folder
results = engine.result.check_all()
for name, df in results.items():
    print(f"{name}: {len(df)} rows")

Supported result types:

• Load case: LCEF (element force), LCED (element displacement), LCND (node displacement), LCBF (boundary reaction), LCTL (tendon loss), LCS (element stress)
• Envelope: EnvBF (boundary reaction), EnvEF (element force), EnvES (element strain), EnvS (element stress), EnvND (node displacement)

Requires pandas to be installed: pip install pandas

Complete Example

from pyosis.core.engine import OSISEngine

engine = OSISEngine()
engine.clear()

# Control parameters
engine.control.set_gravity_acceleration(9.8066)
engine.control.set_calc_tendon(True)
engine.control.set_calc_concurrent_force(True)
engine.control.set_calc_shrink(True)
engine.control.set_calc_creep(True)
engine.control.set_calc_shear(True)
engine.control.set_calc_relaxation(True)
engine.control.set_mod_loc_coor(False)
engine.control.set_inc_tendon(True)
engine.control.set_nonlinear(geom=False, link=False)

# Sections
engine.section.create_circle("Circle Section 1", d=0.219, tw=0.012, no=1)
engine.section.create_circle("Circle Section 2", d=0.180, tw=0.008, no=2)

# Materials
engine.material.create_steel(
    "Steel 1", eCode="JTGD64_2015", eGrade="Q345", dDmp=0.05, no=1
)

# Nodes
engine.node.create(0, 5, 0, no=1)
engine.node.create(15, 5, 0, no=2)
engine.node.create(7.5, 0, 0, no=3)
engine.node.create(20, 0, 0, no=4)

# Elements
engine.element.create_beam3d(1, 3, nMat=1, nSec1=1, nSec2=1, no=1)
engine.element.create_beam3d(2, 3, nMat=1, nSec1=2, nSec2=2, no=2)

# Boundaries
engine.boundary.create_general(no=1)
engine.boundary.get(1).assign("a", [1, 2])

# Loads
lc = engine.load.create(
    "Custom Load Case 1",
    load_case_type="USER",
    prompt="Two forces applied at nodes 3 and 4"
)
lc.create_nforce(3, dFx=0, dFy=-1000000, dFz=0)
lc.create_nforce(4, dFx=200000, dFy=0, dFz=0)

# Solve
engine.solve()

Important Notes

1. OSIS must be running: Before executing code, ensure the OSIS software is launched and logged in. pyosis communicates with OSIS via HTTP.
2. Exception handling: All operations throw RuntimeError on failure. It is recommended to add exception handling in production code.
3. Stateless design: Managers do not cache data. Every query method (all(), get(), filter()) fetches fresh data from OSIS via HTTP. This ensures consistency but incurs network overhead. Cache results locally when iterating in loops.
4. Number uniqueness: When explicitly specifying no, if the number already exists, the behavior depends on the OSIS underlying implementation (usually overwrites or raises an error).

More Resources

• tests/: Example code for each module
• templetes/: Complete bridge modeling template projects