Conceptual Design

Brainstorming

Brainstorming is based on an informal approach to problem solving, encouraging people to generate a vast variety of ideas and solutions, sometimes seemingly weird and odd, but that can contain rational seeds and stimulate mental capabilities of people leading them to the expedient results.

• Individual brainstorming

In the conventional brainstorming concept, individual brainstorming is considered if not impossible but at least inefficient, since “normal” number of participants should count between six and ten. On the other hand, in most cases group brainstorming can be less efficient because people pay so much attention to other people that they do not generate ideas of their own, or they forget these ideas while they wait for their turn to speak.

• Group brainstorming

The main method of the brainstorming requires involvement of several members of the project team, ideally between six and ten. This number involves all expertise, imagination, and open mind of all team members. An idea proposed by one team member can be grasped by another one, possibly, more creative and experienced, and taken to the next stage.

Selection of evaluation criteria

Selection of evaluation criteria is an important step in evaluation of different concepts developed in the project. Evaluation criteria directly relate to customer’s needs, determining the quality of the proposed solutions and their compliance with the project requirements.

All evaluation criteria fall under five major categories.

• Relevance
• Efficiency
• Effectiveness
• Impacts
• Sustainability

Generation of alternatives

Given that an iterative process is required to solve an engineering problem and that design constraints need to be respected, generation of the concept alternatives and selection of conceptual design is the most critical step in product development. Concept generation involves multiple steps, as well as several selection methods.

The overall concept generation process consists of the two main phases – ideation and concept screening – and can be accomplished in four major steps.

1. Clarification and decomposition of the problem
2. Search for Solutions
3. Analysis and Exploration of the Solutions
4. Refining the Solutions

The entire design process is an iterative process. The same applies to any of its phases and steps. Therefore, the concept generation process is also cyclical. With any new information and conditions popping up during concept generation and evaluation, you may need to go back into a previous step, whether it is a brainstorming session, or even a data search. In this way, the list of proposed solutions can be refined and improved.

Engineering analysis and mathematical modelling in design

• Types of engineering analysis

Most of the design activities require different types of engineering analysis that address specific aspects of the design process and the product under design. Engineering analysis can be applied to any type of product development and accompanying research.

Roughly, the types of engineering analysis can be divided into two main categories: qualitative and quantitative analysis. However, such classification is very relative, since each of these categories may require involvement of the other one during design process.

Mechanical engineering analysis can be performed for both the entire design and for each of its subsystems, helping to evaluate and compare different alternatives, and decide which one better meets the requirements.

Quantitative engineering analysis is based on mathematical models that include several phases of the development. When engineering analysis is accomplished, the obtained parametric (mathematical) solution is transferred to the physical model by converting and implementing the obtained results into a real-time engineering model.

• Main stages of general engineering analysis

1. Identification of the physical problem and forming the list of specifications for it.
2. Idealization and assumptions of actual physical situations for subsequent mathematical analysis.
3. Mathematical modeling and analysis using suitable mathematical formulations/model and obtaining solution of a specific engineering problem.
4. Interpretation of results: conversion of the analytical results into physical parameters and requirements.

Evaluation of design solutions and decision making

When all customer needs and designed requirements are fully defined, you can start to generate multiple design solutions, or concepts. This procedure was described in detail earlier. The next step is to choose only one solution that matches the initial requirements and specifications in a best way.

• Criteria selection

Evaluation criteria may be used as well as optimization criteria when optimization is parts of the design process.

• Decision making

Returning to the selection of the concept to develop, you may use an evaluation procedure consisting of the three major steps:

1. Screening, that takes place after the brainstorming session. Here, the team must eliminate all those concepts that are not feasible.
2. Comparison, where all remaining concepts must be evaluated and compared in compliance with the adopted evaluation criteria.
3. Decision making, and here the best concept is selected for further development.

• Pugh matrix

One of the most effective tools for the selection among several candidate design options is the Pugh matrix. The matrix is built when evaluation criteria are identified and clearly defined.

An example of the Pugh matrix is given here.