Untitled Quiz

Engineering Design Process

• The core of the design process is finding a solution to a need.
• Needs can involve improving current conditions, fixing problems, or deriving uses for new ideas.
• Engineering is about gaining a desired outcome, achieved through methodical problem-solving.
• Engineers are seen as problem-solving specialists using established concepts, experiments, and previous discoveries.

Design Steps

• Stage 1: Identifying the design problem.
• Stage 2: Developing problem-solving concepts and ideas.
• Stage 3: Creating a compromise solution.
• Stage 4: Producing prototypes or models.
• Stage 5: Constructing working drawings.

Step 1: Identifying a Need

• Needs, or problems to be solved, are often discovered by the product users (customers).
• Customers can be retail consumers or other teams in a product development process.

Step 2: Establishing Design Criteria and Constraints

• Design criteria define the requirements for the product.
• Criteria are derived from user needs and explain physical and functional characteristics.
• Examples of criteria include shape, size, weight, speed, ruggedness, and ease of manufacturing.

Step 3: Evaluating Alternative Designs

• Researching past solutions helps identify limitations and potential avenues for improvement.
• Evaluate at least two to three alternative designs, considering available technology, revisions to existing designs, or novel solutions.

Development of Alternative Designs

• The process involves creativity use of engineering tools, Computer-Aided Design (CAD), and computer modeling
• The development process includes stress analysis, material science, and manufacturing processes.
• All constraints—available materials, personnel, and facilities—must be taken into account.

Step 4: Building a Prototype of the Best Design

• Select the design that best fulfills the criteria and constraints.
• A prototype is a functional small-scale representation of a new type or design.
• Cost limitations may lead to partial or reduced-scale models. Prototype definitions:
  • An original model upon which something is patterned
  • A standard or typical example
  • A full-scale, functional form of a new type or design

Step 5: Testing and Evaluating the Prototype

• Develop a test plan to evaluate the prototype against established design criteria.
• Test the prototype under actual or simulated operational conditions.
• Customer feedback is crucial in the product testing phase.

Step 6: Analyzing Test Results, Making Design Changes, and Retesting

• Evaluate test results to identify design flaws.
• Implement corrections and repeat the testing process.
• Document all analyses, adjustments, and testing in a project journal.

Design Requirements

• Requirements delineate the necessary features of a system.

• These characteristics are specified before and during the design.

• User/customer needs are the foundation of all other system requirements.

• Requirements identify the essential needs of a system for it to be functional and valuable.

• Requirements clarify a common understanding of desired system properties.

• Two types of requirements: Mandatory and preference.

• Mandatory requirements specify essential conditions for system acceptability, often stated using "shall" and "must."

• Preference requirements describe desired characteristics to improve user experience, usually using "should" or "want."

Defining the Customer

• The customer encompasses anyone with the right to impose requirements on the design.
• This includes end-users, operators, bill payers, owners, regulatory agencies, victims, and sponsors.
• Systems Engineering considerations must account for both the product itself and how it's made, and therefore must also include testing customer of the process.

Stating the Problem

• Clearly and unambiguously define the problem.
• State the desired state if the problem did not exist, rather than focusing on preconceived solutions.
• Alternatively, focus on the deficiency to be rectified, stimulating more design options.

Sources of Requirements

• A list of potential factors that necessitate requirements for the design.
• Examples: Input-Output, Technology, Performance, Cost, Trade-offs, and System Test.
• Other factors include Functional, Performance, Constraints, Verification, and Programmatic.
• The EIA/ANSI-632 standard lists only three criteria: Functional, Performance, and Constraints.

Input-Output

• Requirements relating inputs and outputs of a system—example for an electronic amplifier.

Technology

• Characteristics of hardware, software, or both that limit or enable the system design.

Performance

• Requirements for quantity, quality, coverage area, timeliness, and readiness.

Cost

• Manpower, resources, and monetary factors. Cost limitations may affect design parameters.

Trade-off

• Different relative values of performance and cost criteria. Example, assigning weights (0.6 for performing characteristics and 0.4 for cost).

System Testing

• Ensures design and system satisfy the specified requirements. Example with electronic amplifier (audio input).

Company Policy

• Corporate policies can define the requirements relating to the design.

Business Practices

• Corporate policies may include work breakdown structures, PERT charts, safety procedures, risk assessment, and investment return requirements.

Systems Engineering

• Systems and software design requirements may include mandatory Readme files for hardware and software.

Project Management

• Access to source code for software needs may be a prerequisite.

Marketing

• Focus on exciting and delighting the customer. Features that meet previously unstated customer needs are included here (e.g., customer need for portability was unknown in the 1970s).

Manufacturing Processes

• Requirements relating to the manufacturing process (e.g., the need for a clean room for semiconductor manufacture).

Design Engineers

• Design engineers specify "build-to," "code-to," and "buy-to" requirements for products and "how-to-execute" requirements for processes.

Reliability

• Design reliability can be a performance metric or a separate category.

Safety

• Safety requirements concerning behavior under normal and abnormal conditions.

The Environment

• Impact of environmental factors such as banning ozone-depleting chemicals or other regulations.

Ethics

• Ethical considerations regarding testing on human subjects may form requirements.

Intangibles

• Requirements for factors that are difficult to quantify, such as customer preferences, aesthetics, company prestige, technology leadership, or business expansion.

Common Sense

• Unstated requirements assumed to be common knowledge; for instance, certain design characteristics about humans (e.g., they have two hands).

Laws and Standards

• Laws, standards (e.g., building codes), and regulations may define system requirements.

The Customer

• Statements of fact, assumptions, and expectations of end-users create specific requirements. These may arise from documented needs, acquisition, or mission analyses.

Legacy Requirements

• Customer requirements may be implicitly understood based on prior systems' design experiences (e.g., a new system must be as durable as an old one).

Data Collection Activities

• To understand existing systems, apply existing data collection methods to determine system requirements.

Other Sources

• Further system requirements can come from varied factors such as human factors, environment, user, operator, potential victims, management, company goals, schedule, and other factors.

Validating a System

• Confirming building the right system that has the expected outcome, meeting customer needs, and completeness.

Validating Requirements

• Consistency, realistic construction from requirements, and verification that the created system meets the requirements.

Verifying a System

• Checking that the built components match the design requirements, guaranteeing reliable development phases and a smooth transition from design to production.

Verifying Requirements

• Processes of examination, testing, or demonstration to prove a requirement's fulfillment. Ensuring that validated requirements are capable of being implemented (e.g., ensuring there is no technological limitation). This is an ongoing process. ISO-9000 guidance also exists.

Prototyping

• Prototyping represents the practical building of a product based on the detailed design. The goal is producing a working item that follows all the described parameters. Any needed revisions are identified during this process.

Prototypes: Purposes

• Functional prototypes demonstrate the system's ability to operate in a specified manner.
• Look-and-feel prototypes showcase system aesthetic quality (appearance).
• Role prototypes illustrate usability for the end-user by identifying practical use-cases.