Podcast
Questions and Answers
Which of the following is NOT a step in the material selection strategies?
Which of the following is NOT a step in the material selection strategies?
It is essential to disregard previous choices when making new decisions in the design process.
It is essential to disregard previous choices when making new decisions in the design process.
False
What is the main criterion used for ranking candidates in material selection?
What is the main criterion used for ranking candidates in material selection?
Maximizing or minimizing a specific criterion based on performance and behavior.
The iterative process should always pay attention to one’s own _____ during material selection.
The iterative process should always pay attention to one’s own _____ during material selection.
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Match the following steps in the material selection process with their descriptions:
Match the following steps in the material selection process with their descriptions:
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What is the primary material used in the design of the peeler's handle?
What is the primary material used in the design of the peeler's handle?
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The oval shape of the handle is considered aesthetically pleasing and popular at the time.
The oval shape of the handle is considered aesthetically pleasing and popular at the time.
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What ergonomic purpose do the fins serve in the design?
What ergonomic purpose do the fins serve in the design?
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The manufacturing process involves molding the material known as __________.
The manufacturing process involves molding the material known as __________.
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What is a key aesthetic feature of the handle's design?
What is a key aesthetic feature of the handle's design?
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Match the design features with their corresponding purposes:
Match the design features with their corresponding purposes:
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What is essential when ranking candidates after screening?
What is essential when ranking candidates after screening?
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The countersunk hole in the design is intended to have a more pronounced appearance.
The countersunk hole in the design is intended to have a more pronounced appearance.
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The top-ranking candidate is always suitable for the target use case.
The top-ranking candidate is always suitable for the target use case.
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What is the purpose of the holding tolerance of the fin shape in the peeler's design?
What is the purpose of the holding tolerance of the fin shape in the peeler's design?
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What is used to quantify the overall importance of multiple objectives in candidate ranking?
What is used to quantify the overall importance of multiple objectives in candidate ranking?
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A performance index allows for ranking based on the measure of __________.
A performance index allows for ranking based on the measure of __________.
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Match the following performance properties with their descriptions:
Match the following performance properties with their descriptions:
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What should be checked to ensure the suitability of selected materials?
What should be checked to ensure the suitability of selected materials?
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Performance indices only consider single properties for material ranking.
Performance indices only consider single properties for material ranking.
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What do performance indices allow in terms of property ranking?
What do performance indices allow in terms of property ranking?
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Which material is known for having a good reputation and being biodegradable?
Which material is known for having a good reputation and being biodegradable?
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Soft Polymer Foam is a renewable resource.
Soft Polymer Foam is a renewable resource.
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What is an important tool used for material selection?
What is an important tool used for material selection?
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Cork is primarily produced in _____ and Portugal.
Cork is primarily produced in _____ and Portugal.
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Match the material with its characteristic:
Match the material with its characteristic:
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What aspect does material selection NOT primarily consider?
What aspect does material selection NOT primarily consider?
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Production time of plywood is slower compared to soft polymer foam.
Production time of plywood is slower compared to soft polymer foam.
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What should be considered as part of the requirements in material selection?
What should be considered as part of the requirements in material selection?
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Which material is suggested as an optimal choice due to its performance characteristics?
Which material is suggested as an optimal choice due to its performance characteristics?
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The side length of the beam is considered a free variable in the material selection process.
The side length of the beam is considered a free variable in the material selection process.
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What happens to the beam's geometry when different materials are selected?
What happens to the beam's geometry when different materials are selected?
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To maintain a fixed mass with lower densities, a ______ beam is required.
To maintain a fixed mass with lower densities, a ______ beam is required.
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Match the material with its property regarding beam selection.
Match the material with its property regarding beam selection.
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What does the variable 'α' equal when using the formula for mass calculation?
What does the variable 'α' equal when using the formula for mass calculation?
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Only two parameters are considered for material selection according to the guidelines.
Only two parameters are considered for material selection according to the guidelines.
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What formula represents the relationship between mass, density, length, and area?
What formula represents the relationship between mass, density, length, and area?
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What is the purpose of selecting the material of a beam in this design problem?
What is the purpose of selecting the material of a beam in this design problem?
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The mass of the beam increases with higher values of density (ρ).
The mass of the beam increases with higher values of density (ρ).
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What equation represents the deflection of a beam in three-point bending?
What equation represents the deflection of a beam in three-point bending?
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The second moment of area for a beam with square cross-section is given by _____.
The second moment of area for a beam with square cross-section is given by _____.
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Match the symbols with their corresponding meanings in beam bending equations:
Match the symbols with their corresponding meanings in beam bending equations:
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What is the relationship between performance and mass in this design problem?
What is the relationship between performance and mass in this design problem?
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What variable is being eliminated in the mass formula for the beam design?
What variable is being eliminated in the mass formula for the beam design?
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The stiffness of a beam does not affect its deflection under load.
The stiffness of a beam does not affect its deflection under load.
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Study Notes
Engineering Design and Material Selection
- Lecture 11 focused on material selection
- Key figures and lecturers included Kristina Shea and Tino Stankovic
- Material selection strategies for design processes were discussed
Course Schedule
- The course schedule outlines topics, case studies, quizzes, and lecturer assignments for each week
- A different lecturer delivers each lecture
- Different case studies are used each week
Learning Objectives
- Understanding factors influencing material selection during design processes
- Learning about Ashby charts and how to create and use them for material selection
- Learning strategies for material selection and applying them to examples
Oxo Goodgrips Peeler
- Material: Santoprene (a polymer that behaves like rubber)
- Oval Handle: Ergonomically shaped for handgrip and comfort. Aesthetically popular at the time
- Manufacturing: molding process for easier production
- Counter-sunk Hole: Improved ergonomics for use, reduced cost by reducing material usage. Aesthetically improves appearance.
- Fins: Enhance grip with fingers and thumb. Curve echoes handle shape for a seamless aesthetic. manufacturing considerations.
Challenge: Suitable Materials
- Many materials are suitable, but selecting the best one presents a challenge.
- Questions to consider about material selection:
- How to choose from the many materials?
- What is a helpful strategy?
When do we select materials? — Stages
- The material selection process occurs at different stages of product development:
- Phase 0: Planning
- Phase 1: Concept Development
- Phase 2: System-Level Design
- Phase 3: Detail Design
- Phase 4: Testing & Refinement
- Phase 5: Production Ramp-Up
- Materials selection is an iterative process, often revisiting previous choices.
Material Selection Strategies – General Approach
- The strategies include translation, screening, ranking, and validation
- Translation: Understanding design requirements, objectives, and constraints.
- Screening: Identifying viable materials that meet constraints, using attribute limits.
- Ranking: Prioritizing materials based on performance measures that satisfy design objectives.
- Validation: Investigating the suitability of top-ranked candidates through documentation and usage explorations.
- The approach can be depicted in a flow chart. Multiple steps may be involved at different stages of product development.
Material Selection – General Approach – Additional Details
- Design Requirements: Specifications that define how the product should operate.
- Function: Defining what the product should do.
- Objectives: Measurable goals like cost.
- Constraints: Limitations like size or temperature resistance.
Material Selection Strategies – Computer-Aided Material Selection — General Approach
- Computer-aided selection for vast materials can be helpful.
- Specific software allows for any combination of selection criteria, including material properties such as density, price, mechanical properties, and thermal properties
One-Dimensional Material Selection
- A method for selection using a single property (e.g. Young's modulus)
Two-Dimensional Material Selection - Ashby Charts
- Graphic method comparing/contrasting material properties (e.g., Young's moduli and density)
- Displays materials suitable for specific use cases
- An approach to guide material selection, involving log scales for range and properties.
Two Dimensional Material Selection – Performance Index
- A strategy for evaluating material properties using performance index and guidelines.
Two-Dimensional Material Selection – Log Scales
- Using log scales for wider ranges allows for visualization of material properties to suit potential applications
- Power functions can be shown graphically to illustrate properties
Example: Minimum Mass Design — Stiffness — Beam in Bending
- Identify the parameters to be considered. The objective here is to minimize the mass of a beam.
- Develop relevant equations for deflection and mass
Two-Dimensional Material Selection — Ashby Charts
- Use of a 2D chart to plot contrasting/complementary material properties
- Selecting feasible materials
- Limiting material properties to guide selection.
Beyond 2D Material Selection
- Need for multi-dimensional analysis
- Computer aided material search
- Material parameters
- Parameters to optimize
Case Study: Ski Core
- Requirements: Bending stiffness tuned to the skier, light weight, low CO2 footprint, and geometry constraints.
- Objectives and constraints for which materials are suitable or feasible.
Step 1: Translation
- Requirements for the ski core, including bending stiffness, dimensions, and material properties.
Step 2: Screening
- Screening out materials that do not meet the yield strain or Young modulus constraints
- Focus on materials that meet constraints. Materials can be grouped for easier handling and review.
Step 3: Ranking
- Ranking various materials, based on different criteria and objectives
- Comparing different materials considering cost, CO2 footprint and density.
Step 4: Validation
- Validating the best materials in the selection process
- Investigating the suitability of materials for use, based on various criteria, including manufacturability
Question: Which material would you choose?
- Choice question involving cork, soft polymer foam, and plywood as potential options for ski core material.
Material Selection – Wrap Up
- Material selection considers desired function, manufacturability, and sustainability in design processes.
- Generalized material selection can narrow down the list of suitable materials using screening and ranking.
Exercise 11
- Identifying the best materials suitable for objects like a diving board, a hatchet, or skateboards.
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Description
Test your knowledge on material selection strategies and design principles. This quiz covers key steps in the material selection process and the criteria for evaluating materials for product design. Enhance your understanding of both aesthetic and ergonomic considerations in material choice.