Planar truss span structural optimization (deflection minimization)

A fixed-joint binary optimization problem that selects candidate planar-truss members to minimize deflection subject to factor-of-safety and mass thresholds.

See Optimization Problem Catalog for the optimization family index.

Quick Facts

Field	Value
Problem ID	planar_truss_span_deflection_min
Problem Family	optimization
Implementation	design_research_problems.problems.optimization._truss_topology:PlanarTrussEngineeringOptimizationProblem
Capabilities	baseline-solver, bounded-variables, external-adapter, optional-evaluator, statement-markdown
Study Suitability	none
Tags	optimization, truss, structural, binary, deflection

Taxonomy

Formulation

binary_optimization

Convexity

nonconvex

Design Variable Type

discrete

Is Dynamic

no

Orientation

engineering_practical

Feasibility Ratio Hint

0.05

Objective Mode

single

Constraint Nature

hard

Bounds Summary

one binary variable per candidate member over a fixed planar truss joint set

Tags

optimization, truss, structural, binary, deflection

Statement

Choose a planar truss topology over a fixed support span and a fixed set of candidate joints. Each binary design variable decides whether one candidate member is present. The optimizer builds a concrete PlanarTrussState, runs the real trussme structural analysis, and minimizes structural deflection.

Feasible candidates must satisfy a minimum factor of safety and a maximum mass threshold. The built-in baseline uses deterministic binary enumeration with cheap graph and crossing prechecks plus hard structural thresholds.

Problem Shape

Field	Value
Design Variable Count	15
Bound Summary	one binary variable per candidate member over a fixed planar truss joint set
Total Constraint Count	5
Equality Constraint Count	0
Inequality Constraint Count	5

Variable Bounds

Variable	Lower Bound	Upper Bound
x[0]	0	1
x[1]	0	1
x[2]	0	1
x[3]	0	1
x[4]	0	1
x[5]	0	1
x[6]	0	1
x[7]	0	1
x[8]	0	1
x[9]	0	1
x[10]	0	1
x[11]	0	1
x[12]	0	1
x[13]	0	1
x[14]	0	1

Manifest Parameters

Key	Value
candidate_point_fractions	[[0.25, 0.5], [0.5, 0.5], [0.75, 0.5]]
load_magnitude	1000
max_height	5
maximum_mass	20
minimum_fos	1
objective_metric	deflection-min
span	10

Library Interface

• generate_initial_solution(seed=None)

• objective(x)

• evaluate(x)

• solve(initial_solution=None, seed=None, maxiter=200)