What is Conceptual Design?
The Design Concept is the first step of implementing the machine Requirement into an actual design.
The distinction between Requirement and Concept may be blurred - as a Requirement may be so detailed that it specifies actual technology/design choices.
In the limit of a fully-detailed Requirement - we have a concept.
In the limit of a concept being filled in with technical details - we have a Technical Design.
Jose Urra sez: When I work I differentiate requirements from specifications. A design concept and its unfolding development is an attempt to specify the way in which requirements are met. Requirements can be stated without knowing in detail (specifically) how something is going to be achieved, they can be a set of goals or wishes that need to be verified. A concept is a model of a problem-solution unity more or less specified, or partially specified. Developing a concept thus, is the process of verifying the feasibility of the design concept. The rationale behind checking requirements is different from specifications. Requirements need validation - insofar as to check that a given requirement is needed, not if it is feasible in detail. Validation of a Concept detail is used when a concept is refined enough - as a minimum check to determine if a design detail is needed. Verification of a concept is the determination of its feasibility - such as by doing calculations.
How Does Conceptual Design Relate to Other Aspects of a Product Development Process?
Once we have defined Conceptual Design, we can proceed to further refinement of concept towards a technical design. Upon sufficient refinement, there is sufficient information to manifest the technical design in the form of 3D CAD. The Modular Breakdown step is where the concept can be refined further by examining the constituent modules. The Modular Breakdown is the best place to capture the transition from concept to the actual design. Once the actual design (3D CAD) is produced - we can do full Calculations including structural, thermal, fluid, and electromagnetic. Partial calculations can be made at the phase of conceptual design - with back of the envelope calculations just to get an idea of basic feasibility. All of these steps can be done at various levels of product-service system organization: the system, machine, module, and submodule (part) levels.