Handbook of Reliability, Availability, Maintainability and Safety in Engineering Design - Part 71 studies the combination of various methods of designing for reliability, availability, maintainability and safety, as well as the latest techniques in probability and possibility modelling, mathematical algorithmic modelling, evolutionary algorithmic modelling, symbolic logic modelling, artificial intelligence modelling, and object-oriented computer modelling, in a logically structured approach to determining the integrity of engineering design. . | 684 5 Safety and Risk in Engineering Design Fig. Detail design model of the scrubber in the layout of a gas cleaning plant structural and geometric feature of the design. A schematic design model of the gas cleaning plant is graphically illustrated in Fig. . After evaluation of the design variables and constraints describing the structural and geometric feature of the design a detail design model is prepared. In process engineering design a detail design model typically has variables and constraints representing embodiment structure and assembly and dynamic flow and energy balance information of the process layout. A detail design model of the scrubber system of the gas cleaning plant is graphically illustrated in Fig. . A detail design model is computationally represented as a network of design variables and constraints that can be manipulated to identify critical equipment for example using constraint-based techniques Smithers et al. 1990 . The network of design variables and constraints of a detail design model can be partitioned into smaller sets to identify relations. AI-based search methods such as genetic algorithms and neural networks can then be used to find a set of design variable values that best satisfy the constraints. This partition can be done based on the following mathematical relations of the design variables assembly of the detail process model configuration of the systems layout heuristics introduced by designers. Analytic Development of Safety and Risk in Engineering Design 685 A partition of the constraint network identifies a small region of the design space in which for example design variables and constraints are evaluated to identify critical equipment in designing for safety and explored using evolutionary computing techniques such as evolutionary algorithms. a Fundamentals of Evolutionary Algorithms EA Evolutionary algorithms EA are stochastic search and optimisation heuristics derived from classic evolution theory. The
