Materials Engineering in Lightweight Design

The activities presented in this curriculum module were developed to give middle and high school students an opportunity to experience the engineering design process from the perspective of a materials scientist. This package includes:

  • Curriculum alignment and pacing guides
  • An introduction to lightweight design
  • Videos illustrating the design challenge of protecting automobile passengers in a side crash
  • Equations needed to optimize student designs to make stiff and mass efficient beams
  • Lab worksheets and teacher guides
  • Short video clips that can be used to preview the labs with your students
  • Online videos about an athlete who happens to be a lower limb amputee. These videos focus on the materials engineering involved in creating her prosthetic, and how the limits of current materials and processes affect what she can do.

The lab activities are designed to be modular and inexpensive. Depending on your objectives and time available, you can offer the students one to four labs with an optional crash test for each lab. We have a suggested order for the labs, but feel free to adapt them to suit your students.

NGSS Standards Addressed By This Module:

We believe these activities will be useful beyond Materials Science elective courses.   They should fit well in physics and math courses, and satisfy NGSS requirements to teach the engineering process.

The activities in this module involve creating beams of different sizes and shapes, and made from different materials, with a goal of making the lightest possible beam that meets a required deflection limit under a fixed force (or energy if you opt for the crash test options). We believe the content meets these NGSS requirements:

Performance Expectations for Engineering Design:

HS-ETS1-1. Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that account for societal needs and wants.

HS-ETS1-2. Design a solution to a complex real-world problem by breaking into smaller, more manageable problems that can be solved through engineering.

HS-ETS1-3. Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.

Disciplinary Core Ideas for Engineering Design and Physical Science:

ETS1.A – Defining and Delimiting Engineering Problems

ETS1.B – Developing Possible Solutions

ETS1.C – Optimizing the Design Solutions

PS3.B – Conservation of Energy and Energy Transfer

Science and Engineering Processes:

Asking questions and defining problems

Planning and carrying out investigations

Analyzing and interpreting data

Developing and using models

Constructing explanations and designing solutions

Engaging in argument from evidence

Using mathematics and computational thinking

Obtaining, evaluating, and communicating information

Crosscutting Concepts:

Cause and effect: mechanism and prediction

Scale, proportion and quantity

Systems and system models

Energy and matter: flows, cycles and conservation

Structure and function

Connections to Engineering, Technology and Applications of Science:

Interdependence of Science, Engineering and Technology

Influence of Science, Engineering and Technology on Society and the Natural World

Connections to the Nature of Science:

Scientific Investigations Use a Variety of Methods

Download the Lessons

Entire Unit: Materials Engineering In Lightweight Design

We introduce the concept of lightweight design using the complex shapes and local reinforcement of vulture bones as an example.   Then, we focus on the design problem of protecting automobile passengers from side crashes.    Passenger protection is a critical function of the “B Pillar” which is the metal beam between the front and rear passenger doors that houses your seatbelt retractor, front door latch, and rear door hinge.   B Pillars are complex assemblies of a range of materials having different strengths and thicknesses to meet crash test requirements with minimum mass.   Unlike traditional pasta bridge competitions, the design objective in our labs is to minimize deflection under a given load or crash energy, rather than to support a given force.     Four labs are offered.   Depending on your syllabus, you can do one, two, or all of the labs.   Each lab focuses on a different aspect of the B Pillar beam design problem.

Download the complete curriculum package including curriculum alignment, background information, lab procedures and teacher preparation notes, classroom discussion starters and more here:  Materials Engineering in Lightweight Design Teacher Package Rev 5

This 35 minute video provides an overview of the entire curriculum package including demonstrations of the labs: 

This link will show you the Insurance Institute for Highway Safety (IIHS) Side Crash Test Video:

Lab 1: Shape Variable

The stiffness of beams depends on both the beam material and the beam shape.   This introductory lab isolates the shape variable.   Students fold cardstock into two different shape beams – one tall and narrow and one short and wide.   The amount of weight needed to deflect the beam a given distance is measured with the beams free standing, and then with the beams supported along the edges to better simulate the “B Pillar” between the front and rear doors of a passenger card when it is subjected to a side crash.   (Crash tests are conducted with the doors closed which provides some support to the pillar.)

Lab 1 module including background information, teacher preparation notes, and student worksheets:

Lab 1 Version A Stacked Weights Final

Lab 1 Version B Suspended Weights Final

Lab 1 Video:

Lab 2:  Material Effects on Beam Stiffness

This lab isolates the effect of material choice on beam stiffness.    Solid beams are cut from extruded and expanded polystyrene insulation boards with different densities, then tested in cantilever bending.   The extruded polystyrene is much stiffer than the expanded bead polystyrene.    Beam stiffness is calculated from the load-deflection curve and can be used to predict the deflection of a student designed beam in Lab 4.   An alternative approach which builds on Lab 1 is to fill the folded cardstock beams with urethane foam of different densities.     A student reading assignment showing how crash performance of automobiles is improved by filling hollow beams with urethane foam is also available.

Lab 2 Version B Reading Assignment

Lab 2 Version A Solid Foam Beams Final

Lab 2 Version B Cardstock with Spray Foam Beams Final

Lab 2 Video:

Lab 3: Stressed Skin Composites 

(Combined effects of material choice and placement of the reinforcing tape)

Lab 3 builds on Labs 1 and 2 by challenging students to create the most mass efficient composite beam by placing tape on the upper side of a beam.   Students decide where to place the tape and how many layers to use.   The beams can be the solid beams cut from insulation board in Lab 2, or uncooked lasagna noodles.   The cost of the tape can also be considered, and different types of tape (duct tape, packing tape, masking tape…) can be included.    (Bananas are an example of a stressed skin composite.   When you pull on the stem to peel the banana, the skin is stretched and resists the force you apply.)

Lab 3 Stressed Skin Composites Final

Lab 3 Video:

Lab 4:  “Freestyle” (Students optimize beam geometry and material choices)

Lab 4 builds on Labs 1 and 2 by engaging students in the creative process of engineering.   Students choose one or more materials to fabricate a beam, which may include carving material out where it is not needed for stiffness, or adding reinforcements.   The choice of materials is up to the teacher.   Our version uses the insulation board beams from Lab 2a, tape from Lab 3, polyurethane foam from Lab 2b, and reinforcements such as bamboo skewers or pencils.   The winning design is that which requires the most mass (or crash energy)  to deflect the beam a fixed distance per gram mass of the beam.

Lab 4 Freestyle Optimize Material and Shape Final

Classroom Crash Test Ideas

Because our design problem is based on the side impact crash test, students will be eager to crash test their beams.   We have three options to crash test with student safety in mind.   Both fixed and variable crash energy test methods are described so you can choose the option best suited for your students.

Teacher Notes on Classroom Crash Test Methods Final

Crash test methods video:

Classroom Discussion Starter Videos

We prepared three short videos about a young athlete with a lower limb prosthetic to serve as classroom discussion starters.   Nicole Ver Kuilen lost her lower leg to childhood bone cancer.  A year later, her parents signed her up for soccer!   As a young athlete and advocate, she is an inspiration.  We explore how the materials used for the prosthetic affect what Nicole can do, and we were thrilled to get a behind the scenes look at the engineering and manufacturing processes used to make Nicole’s leg.  Each video is 3-4 minutes long.   Example discussion questions for each video are here:  Teachers Notes on Classroom Discussion Starter Videos Final

Episode 1: Nicole Ver Kuilen – Athlete and Amputee
In this video we meet Nicole, and learn how she became an amputee, athlete, and advocate.   We filmed Nicole a few months before she ran, biked, and swam from Seattle to San Diego to raise awareness of the need for prosthetic access.

Episode 2: Materials Challenges In A Prosthetic Limb
Nicole Ver Kuilen explains some of the materials engineering aspects of her prosthetic including corrosion problems, carbon fiber composites, and advanced polymer fabrics.

Episode 3: Materials In A Prosthetic Limb
Nicole’s prostheticist, Natalie Harold, takes us behind the scenes at the University of Michigan prosthetics lab to describe how she selects materials to make prosthetic legs, and some of the design and process technology needed to create these customized limbs.   Natalie’s undergraduate degree was in mechanical engineering, and she is using that training to directly help patients.