Bond graph¶

A domain-independent graphical model of power exchange in dynamic physical systems using effort–flow variable pairs and energy-conserving junctions.

Version: v1 · 2026-09-08 · History
Domain-specific #: 3509
Origin domain: systems engineering
Subdomain: systems engineering

Core Idea¶

Bond graphs unify electrical, mechanical, hydraulic, thermal and other domains through common power semantics; elements represent storage, dissipation, transformation and sources while causal strokes guide equation generation. Power bonds carry conjugate effort and flow, zero and one junctions enforce conservation relations and typed components transform or store energy to produce system equations. The abstraction is therefore identified by a declared carrier, a transformation or constraint over that carrier, and an invariant that tells an analyst whether the named structure is genuinely present.

Scope of Application¶

Bond graph belongs to systems engineering and is useful where the analyst can specify the typed systems engineering carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets, then evaluate the physical boundary and domains, effort and flow variables and units, bond orientation and causality, junctions, storage, resistance, sources and transformers, constitutive laws and conservation checks are explicit. The scope is broad within that domain but bounded by the need for the physical boundary and domains, effort and flow variables and units, bond orientation and causality, junctions, storage, resistance, sources and transformers, constitutive laws and conservation checks are explicit. Conceptual modeling identity only; physical-system design requires validated parameters and qualified engineering.

Clarity¶

The abstraction clarifies a crowded vocabulary by making the physical boundary and domains, effort and flow variables and units, bond orientation and causality, junctions, storage, resistance, sources and transformers, constitutive laws and conservation checks are explicit the center of the account. A claim should name the carrier, the governing operation or relation, the applicable assumptions, and the recognition test.

Manages Complexity¶

Without the abstraction, an analyst must reason directly over many local details: the carrier roles, admissibility assumptions, competing conventions, derived invariants, boundary cases, and proof or validation obligations specific to Bond graph. Bond graph compresses them into the roles in the structural signature. That compression permits comparison across instances without erasing the variables that determine validity. It also exposes which details may be varied safely and which are constitutive.

Abstract Reasoning¶

Identify the carrier. State what the elements, states, objects, or observations are: the typed systems engineering carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets. Reject examples whose alleged carrier belongs to a different problem. 2. Lock the constitutive rule. Express the physical boundary and domains, effort and flow variables and units, bond orientation and causality, junctions, storage, resistance, sources and transformers, constitutive laws and conservation checks are explicit independently of one notation or implementation.

Knowledge Transfer¶

Knowledge transfers strongly among subfields of systems engineering because they reuse the typed systems engineering carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets, Power bonds carry conjugate effort and flow, zero and one junctions enforce conservation relations and typed components transform or store energy to produce system equations., and type the carrier, state every parameter and convention in the definition, test that the physical boundary and domains, effort and flow variables and units, bond orientation and causality, junctions, storage, resistance, sources and transformers, constitutive laws and conservation checks are explicit, compare the nearest accepted identity, and report counterexamples, uncertainty, and limiting cases.

Relationships to Other Abstractions¶

Current abstraction Bond graph Domain-specific

Parents (1) — more general patterns this builds on

Bond graph is a kind of Representation Prime

The proposed strict upward parent is prime:representation.

Hierarchy path (1) — routes to 1 parentless root

Bond graph → Representation → Abstraction

Neighborhood in Abstraction Space¶

Bond graph sits in a crowded region of the domain-specific corpus (12^th percentile for distinctiveness): several abstractions share nearly its structure, so a description that fits it tends to fit its neighbors too.

Family — Engineering Design & Requirements (47 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-09-08