11                  Physical Elements

The physical elements are included as an extension to the Technology Layer for modeling the physical world.

11.1             Physical Elements Metamodel

Figure 99 gives an overview of the physical elements and their relationships. These are based on the Technology Layer.

Figure 99: Physical Elements Metamodel

Note:      This figure does not show all permitted relationships; every element in the language can have composition, aggregation, and specialization relationships with elements of the same type. Furthermore, there are indirect relationships that can be derived, as explained in Section 5.7.

11.2             Active Structure Elements

The equipment element is the main active structure element within the physical elements. This element is used to model structural entities in this layer. It is used to model any physical machinery, tools, instruments, or implements. It strictly models the structural aspect of a system; its behavior is modeled by an explicit relationship to the behavior elements.

The inter-relationships of physical elements are mainly formed by the logistics infrastructure. The path element from the Technology Layer models the relation between two or more nodes, through which these nodes can exchange information or material. The physical realization of a path is modeled with a distribution network; i.e., a physical connection between two or more pieces of equipment (or other physical networks). This can be used to model, for example, rail or road networks, the water supply, power grid, or gas network.

11.2.1           Equipment

Equipment comprises all active processing elements that carry out physical processes in which materials (which are a special kind of technology object) are used or transformed. Equipment is a specialization of the node element from the Technology Layer. Therefore, it is possible to model nodes that are formed by a combination of IT infrastructure (devices, system software) and physical infrastructure (equipment); e.g., an MRI scanner at a hospital, a production plant with its control systems, etc.

Material can be accessed (e.g., created, used, stored, moved, or transformed) by equipment. Equipment can serve other equipment, and also other active structure elements such as business roles and actors, and facilities can be assigned to equipment. A piece of equipment can be composed of other pieces of equipment. Facilities can be assigned to equipment (i.e., equipment is installed and used in or on a facility). Equipment can be aggregated in a location.

The name of a piece of equipment should preferably be a noun.

Figure 100: Equipment Notation

A useful specialization of equipment is vehicle, for describing, for example, trucks, cars, trains, ships, and airplanes.

11.2.2           Facility

A facility is a specialization of a node. It represents a physical resource that has the capability of facilitating (e.g., housing or locating) the use of equipment. It is typically used to model factories, buildings, or outdoor constructions that have an important role in production or distribution processes. Examples of facilities include a factory, a laboratory, a warehouse, a shopping mall, a cave, or a spaceship. Facilities may be composite; i.e., consist of sub-facilities.

Facilities can be interconnected by distribution networks. A facility can serve other facilities, and also other active structure elements such as business roles and actors. A facility can be composed of other facilities and can be aggregated in a location.

The name of a facility should preferably be a noun referring to the type of facility; e.g., “Rotterdam oil refinery”.

Figure 101: Facility Notation

11.2.3           Distribution Network

A distribution network represents the physical distribution or transportation infrastructure. It embodies the physical realization of the logical paths between nodes.

A distribution network connects two or more nodes. A distribution network may realize one or more paths. A distribution network can consist of sub-networks and can aggregate facilities and equipment, for example, to model railway stations and trains that are part of a rail network.

Figure 102: Distribution Network Notation

11.3             Behavior Elements

No separate physical behavior elements are defined. Rather, the behavior elements from the Technology Layer (technology function, process, interaction, service, and event) are used to model the behavior of all nodes, including physical equipment. Since equipment will very often be computer-controlled or in other ways have a close relationship to IT (also think of sensors, IoT), their behavior can be described in an integral way using the existing technology behavior concepts.

11.4             Passive Structure Elements

11.4.1           Material

Material is typically used to model raw materials and physical products, and also energy sources such as fuel and electricity. Material can be accessed by physical processes.

The name of material should be a noun. Pieces of material may be composed of other pieces of material.

Figure 103: Material Notation

11.5             Example

Example 33: Physical Elements

11.6             Summary of Physical Elements

Table 9 gives an overview of the physical elements, with their definitions.

Table 9: Physical Elements

Downloads

Downloads of the ArchiMate documentation are available under license from the Download link within the ArchiMate information web site. The license is free to any organization wishing to use ArchiMate documentation entirely for internal purposes. A book is also available from The Open Group Library as document C197.