3D-Printed Crumple Zones for Impact Testing

ISEF Category: Engineering Technology: Statics and Dynamics

Subcategory: Other  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

Car bumpers protect you by sacrificing themselves first. Your project asks a simple question, can a printed lattice do the same job over and over? That turns a familiar crash problem into a hands-on engineering test. You get to measure how shape changes impact safety.

What Is It?

A crumple zone is a part of a structure that bends, buckles, or collapses on purpose during impact. That sounds bad, but controlled collapse spreads out the force and lowers the peak hit. Think of it like a helmet pad that gets squished to protect your head.

In this project, you would design a 3D-printed lattice, which is a repeating open structure with lots of empty space. When something falls on it, the thin walls buckle in a planned way. That buckling can absorb energy, which is the ability to take in impact before the load reaches the object inside.

You can compare different lattice shapes, wall thicknesses, or print patterns against polystyrene foam. Foam already works like a tiny spring-and-crush system. Your job is to see which structure absorbs more energy for each gram of material used.

Why This Is a Good Topic

This makes a strong science fair topic because you can change one design feature at a time and measure a real engineering result. You can connect it to car safety, packaging, helmets, and drone protection. You will learn about force, energy absorption, buckling, and fair comparison using data, not guesswork.

Research Questions

• How does lattice geometry affect energy absorbed per gram during impact?
• What is the effect of wall thickness on peak force during a drop test?
• Does print orientation change how a lattice collapses and recovers?
• To what extent does a printed lattice outperform polystyrene foam at the same mass?
• Which lattice design gives the best balance between low peak force and high energy absorption?
• How does repeated impact change the performance of a reusable printed crumple zone?

Basic Materials

• FDM 3D printer.
• PLA filament or PETG filament.
• CAD software for lattice design.
• Digital kitchen scale with 0.1 g resolution.
• Measuring tape or ruler.
• A fixed drop guide or release setup.
• Eggs or other fragile test payloads with a consistent mass.
• Polystyrene foam blocks or sheets.
• Protective eyewear.
• Padded catch bin or safety box.
• Smartphone camera for slow-motion recording.
• Calipers for measuring printed dimensions.

Advanced Materials

• FDM 3D printer with controllable infill and layer settings.
• PLA, PETG, or TPU filament.
• Compression test frame or materials tester.
• Load cell with data logger.
• High-speed camera.
• Accelerometer sensor or smartphone motion sensor app.
• CAD software for parametric lattice design.
• Finite element analysis software.
• Digital balance with 0.01 g resolution.
• Calipers.
• Standardized mass dummy or instrumented egg surrogate.
• Safety enclosure for impact testing.

Software & Tools

• Tinkercad: Lets you sketch simple lattice concepts before moving to more detailed design work.
• Fusion 360: Helps you build parametric lattice structures and change one dimension at a time.
• ImageJ: Measures collapse height, crush width, and damage patterns from photos and video frames.
• Python: Helps you calculate impact energy, energy per gram, and summary statistics.
• Google Sheets: Organizes trial data, graphs comparisons, and tracks repeated tests.

Experiment Steps

1. Define the impact problem you want to solve, such as protecting a fragile payload at a fixed drop height.
2. Choose one lattice variable to change first, such as cell shape, wall thickness, or print orientation.
3. Design a fair comparison plan with a foam control, a repeated test method, and one clear performance metric.
4. Build a way to measure impact outcome, such as crush distance, peak deformation, or surviving payload condition.
5. Plan how you will normalize results by mass so you can compare energy absorbed per gram.
6. Set up a repeat test strategy so you can check whether the structure keeps working after the first hit.

Common Pitfalls

• Changing several print settings at once, which makes it impossible to tell which design feature caused the result.
• Using different payload masses between trials, which makes the impact comparison unfair.
• Letting the drop angle vary, which changes how the lattice buckles and skews the data.
• Comparing designs only by whether the egg breaks, which misses the actual energy absorption behavior.
• Ignoring print defects such as weak layer bonding or warped walls, which can make one lattice fail for reasons unrelated to geometry.

What Makes This Competitive

A stronger version of this project would use a real comparison metric, not just a survival check. You could measure force, displacement, and absorbed energy, then normalize by mass so the results mean something for design. Strong entries also test more than one geometry and use statistics to show which design really wins. If you add repeat-impact testing or a tough foam baseline, your project starts to look like engineering research instead of a demo.

Project Variations

• Test different lattice cell shapes, such as honeycomb, triangular, or diamond patterns, and compare energy absorbed per gram.
• Compare the same lattice design in PLA, PETG, and TPU to see how material stiffness changes collapse behavior.
• Use a smartphone accelerometer or load cell instead of egg breakage alone to measure peak impact and crush response.

Learn More

• NASA Glenn Research Center Materials and Structures pages: Search NASA Glenn for crash safety, energy absorption, and lightweight structure resources.
• MIT OpenCourseWare Mechanics of Materials: Find free lecture notes and problem sets on stress, strain, and buckling.
• NIST Materials Data resources: Search NIST for material property references that can help you justify print choices.
• Engineering Village or Google Scholar: Search for review articles on lattice structures, auxetic materials, and energy absorption.
• PubMed: Search for biomechanics papers on impact protection and energy dissipation in protective structures.