Engineering Design and Solutions Flashcards

An engineering team is designing a new commuter bicycle. The marketing department has specified that the bicycle must be priced under $400 and weigh less than 15 kg. The design will be considered successful if it achieves a durability rating of at least 8 out of 10 in stress tests. Which of the following is a design *constraint*?

Answer: Weighing less than 15 kg

In engineering design, constraints are limitations or restrictions on the design, often related to resources, materials, or specific requirements that must be met. [9, 11] Weighing less than 15 kg is a specific, quantifiable limit the design must adhere to. Achieving a durability rating of 8/10 is a criterion, which is a standard for measuring the success or quality of the design. The color and number of gears are design choices, not fundamental constraints in this context.

A student group has identified a problem: the classroom's recycling bin is often contaminated with non-recyclable trash. They have brainstormed several potential solutions. According to the engineering design process, what is the most logical next step?

Answer: Establish criteria and constraints to evaluate the potential solutions.

After brainstorming, the next critical step in the engineering design process is to develop a clear set of criteria (measures of success) and constraints (limitations) for a solution. [1, 10] This framework is essential for systematically and objectively evaluating the brainstormed ideas to determine which one is most likely to be successful before committing resources to prototyping or implementation.

Which of the following best defines a 'trade-off' in the context of engineering design?

Answer: A design choice where improving one desired feature necessitates worsening another.

A trade-off is a fundamental concept in engineering design where a decision must be made to sacrifice one benefit to gain another. [7, 14] For example, making a product stronger (a benefit) might require using heavier materials, thus increasing its weight (a drawback). Engineers must constantly balance these competing criteria to find an optimal solution.

A team is developing a device to purify water in remote areas. They have built an initial prototype. What is the primary purpose of building and testing this first prototype?

Answer: To identify flaws and gather performance data to inform the next design iteration.

A prototype is an early model of a product built to test a concept or process. [2, 5] Its main purpose is to allow engineers to test functionality, identify weaknesses, and collect data that will guide improvements in the next version of the design. [3, 6] It is a key part of the iterative process of refining and optimizing a solution.

An engineer is designing a new ski helmet. The primary criterion is safety, but other important criteria include low weight, comfort, and aerodynamics. The engineer finds that using a denser, thicker foam improves the safety rating significantly but also increases the helmet's weight and reduces its aerodynamic efficiency. This situation is a clear example of:

Answer: The need to make trade-offs between competing criteria.

This scenario perfectly illustrates the concept of a trade-off, which is central to engineering design. [13, 15] The engineer must balance the competing criteria of safety, weight, and aerodynamics. Improving one criterion (safety) has a negative impact on others (weight, aerodynamics). The final design will be a compromise that seeks to optimize the overall solution based on prioritized criteria.

An engineering team has developed and tested three different prototypes for a new, inexpensive solar-powered lamp. The primary goal is to maximize brightness (measured in lumens) while keeping the cost under a $15 constraint. Which prototype should be selected for further development?

Answer: Prototype D: 180 lumens, $14 cost.

The evaluation of a solution requires comparing performance against both criteria and constraints. [14, 15] The hard constraint is a cost under $15. Prototype B fails this constraint, so it must be eliminated. Of the remaining options (A, C, and D), the primary criterion is to maximize brightness. Prototype D provides the highest brightness (180 lumens) while still meeting the cost constraint ($14), making it the optimal choice.