In our previous article, ‘MBSE – Model-Based Systems Engineering’, we introduced the fundamentals of model-based systems engineering. In this technical article, we explore the topic in greater depth and demonstrate how MBSE can help to structure complex development processes, make interdependencies transparent and improve collaboration between different engineering disciplines.

When traditional development approaches reach their limits
Modern products are increasingly becoming complex, integrated systems. Mechanical, electronic, software and sensor components must not only function individually, but also work together as an integrated system. At the same time, demands on quality, functionality and development speed are rising.

In document-based development approaches, information is often managed across various documents, spreadsheets and software solutions. If requirements or system components change, the relevant information must be checked and updated in several places. This can lead to inconsistencies that only become apparent in later stages of development.

This is where Model-Based Systems Engineering (MBSE) comes in: rather than considering individual documents in isolation, the focus is on digital system models. These models represent key properties, structures and interrelationships within a system, thereby supporting a consistent view throughout the development process.

What is MBSE?

MBSE refers to the formalised use of models to support system development. This includes, amongst other things, the capture and management of requirements, the design of the system architecture, as well as analysis, verification and validation.

A model provides an abstract representation of selected aspects of a real or planned system. It highlights interrelationships and creates a common basis on which different specialist disciplines can work.

It is crucial that the models are linked to one another. This makes it possible, for example, to trace which function a particular requirement fulfils and which components are responsible for its implementation. As a result, the impact of changes can be better assessed.

MBSE does not necessarily replace all documentation. Rather, the required documentation and different system views can be derived from the existing models. The aim is to manage information more consistently and to ensure that interrelationships remain traceable throughout the entire development process.

From Requirements to System Architecture: RFLP and SysML
The RFLP approach is one of the methods used to structure system development. The acronym stands for four interrelated levels of analysis:

  • Requirements: What requirements and expectations must the system fulfil?
  • Functional: What functions are required to implement these requirements?
  • Logical: How are the functions logically structured and interconnected?
  • Physical: Which specific components and technical elements make up the system?

This framework helps to systematically link requirements with functions, logical structures and physical implementation. This makes it clear how individual development decisions stem from the original requirements.

SysML (Systems Modelling Language), for example, can be used for modelling. This graphical modelling language offers standardised ways of representing the structures, behaviour and interrelationships of technical systems.

It is important to note that MBSE is not the same as SysML. MBSE describes the overarching methodology for model-based systems engineering. SysML is one possible language for creating the models required for this purpose. Which methods, languages and tools are suitable depends, amongst other things, on the requirements, the complexity of the system and the existing development processes..

What are the benefits of MBSE?
The model-based approach can offer several benefits, particularly in complex development projects.

Greater transparency and better collaboration: A shared system model makes it easier for different disciplines to understand the overall architecture and its interdependencies. It creates a common information base and facilitates coordination between those involved.

Traceable requirements and changes: Links between requirements, functions and components make it easier to trace which elements are affected by a change. This promotes consistency in system information and makes it easier to assess potential impacts.

Early fault detection: Analyses and simulations can help to identify problems as early as the initial development phases – before costly physical prototypes or integration steps become necessary. This may allow faults to be rectified at an earlier stage.

Consistency throughout the lifecycle: The system models can serve as a basis for testing, verification, validation and subsequent changes even beyond the design and development phases. MBSE thus also forms an important building block for digital engineering and can support the development of digital twins.

However, the extent to which these benefits are actually realised depends on the specific implementation, the quality of the models and their integration into existing processes.

What needs to be taken into account during implementation?
MBSE is not merely an IT project. Its implementation requires a coordinated interplay of methods, processes, tools and qualified staff.

Companies should first clarify which challenges they wish to address using the model-based approach. A clearly defined pilot use case can help to test suitable modelling methods, define responsibilities and assess the specific benefits.

Equally important are integration into existing engineering and PLM processes, consistent data management, and clear rules for maintaining and further developing the models. Without coordinated working practices and adequate training, there is a risk that new models will simply create additional data assets rather than bringing about sustainable improvements to existing development processes.

Conclusion: MBSE as a building block of digital engineering
The more complex technical systems become, the more important it is to have transparent interrelationships, consistent information and close collaboration between the relevant disciplines. MBSE offers a structured approach to this by using digital system models to link requirements, architecture and development steps.

Success, however, does not depend solely on the software used. It is only the combination of suitable methods, clear processes, integrated tools and qualified staff that makes the model-based approach an effective component of an end-to-end engineering strategy.