Crush Zone

Rule 5.2.3 provides that a crush zone is defined as structural components outside of the safety cell that are designed to collapse in an effort to absorb some of the impact from a collision without impacting the driver space. The crush zone must provide driver and battery protection from front, side, and rear collisions

Clarification: This rule implies that that there will be a structure composed of lighter-weight metal or composites attached to the frame designed to "crush" in the event of a collision. Foam products can be used to enhance this crush zone, but it must be a part of this lighter-weight structure.

If foam is used to enhance the Crush Zone, that foam must be of a quality that will absorb impacts correctly. Inexpensive Styrofoam or other types of cheap foam are not acceptable. High density foam or honeycomb energy attenuating material is preferred.

Shape of Crush Zone: The shape of the crush zone should be a rectangle providing protection up to 30 cm from the ground. This is designed to prevent intrusion into the driver’s compartment in the event of a side collision. The crush zone must be extended to protect a rear battery compartment.

Composite Materials

Rule 5.2.4 provides that the use of composite materials is permitted on the solar car. However, if composite materials are used in the safety cell, roll bar, or crush zone, the team must send a sample of the materials to a professional organization specializing in destructive testing to verify adequate structural strength and submit the resulting report to Event Officials for evaluation.

Clarification: Scrutineering staff will want to see that you have properly evaluated the use of composite materials used in the safety cell, roll bar, or crush zone. This requires submitting your materials to a professional organization to determine that you have adequate structural strength. [Sample Analysis attached]

Adequate structural analysis should include these tests:

• Tensile Testing (Strength & Stiffness)
• Compression Testing (Crushing & Buckling)
• Shear Testing (interlaminar & In-Plane)
• Flexural Test (Bending)
• Impact & Fracture Testing

Adequate structural testing, should show that a side collision can handle a 3G force. This 3G force is three times the weight of the solar car including the driver. This 3G guideline is suggested for 2026. It will be required in 2027.

The report from the professional testing organization must be submitted with your other registration materials on March 1st unless other wise extended by the Race Director.

Here is a great website that discusses composite materials stress testing: https://www.addcomposites.com/post/mechanical-testing-of-composites

PROPOSED CHANGES FOR 2027

Many teams will be planning new vehicles in preparation for upcoming solar car racing events. We are making a formal announcement that several new Rules will be included in the 2027 Rules Document. They will not be required in 2026, but are intended to help guide your construction in preparation for 2027.

If you are building a new car in 2026, you should consider following these new guidelines. There will be no “grandfathering” of vehicles in 2027. Anti-Intrusion to the crush zone area.

Rule 5.2.3.3 - The area covered by the crush zone must have a solid anti- intrusion plate to prevent material from entering the driver compartment in the event of an accident. Crush zone material must be bonded to the anti-ingress plate.

Rule 5.2.3.4 - Acceptable materials for crush zones are high density foam or honeycomb energy attenuating material.

APPENDIX FOR COMPOSITE DESTRUCTIVE ANALYSIS

These tests are widely used in the aerospace and automotive industries to validate material performance. A summary of the verified standards and their specific applications is provided below:

1. Tensile Testing (Strength & Stiffness)

• ASTM D3039: The primary standard for polymer matrix composites. It provides data on ultimate tensile strength, modulus of elasticity, and Poisson's ratio.
• ISO 527-4 & 527-5: These are the international counterparts.
• ISO 527-4 is for isotropic and orthotropic materials (like fabrics/mats), while ISO 527-5 is dedicated to unidirectional fiber-reinforced composites.

2. Compression Testing (Crushing & Buckling)

• ASTM D6641: Utilizes a Combined Loading Compression (CLC) fixture. This is currently the most popular method due to its simplicity and ability to test both tabbed and untabbed specimens.
• ASTM D3410: Uses shear loading via a specialized fixture (often called the IITRI fixture) to introduce compression into the material.
• ISO 14126: The international standard for in-plane compressive properties of fiber-reinforced plastic composites.

3. Shear Testing (Interlaminar & In-Plane)

• ASTM D2344 (Short-Beam Shear): A common quality control test used to determine the interlaminar shear strength (ILSS)—how well the resin holds the fabric layers together.
• ASTM D5379 (Iosipescu): Uses a V-notched beam to apply a highly uniform shear force to the material.
• ASTM D3518: A tensile test performed on a laminate to determine the in-plane shear response.

4. Flexural Testing (Bending)

• ASTM D7264: Standard for determining the flexural (bending) properties of polymer matrix composites using three-point or four-point loading.
• ISO 14125: The equivalent international standard for fiber-reinforced plastic composites in flexure.

5. Impact & Fracture Testing

• ASTM D7136: Measures damage resistance of a composite plate after being struck by a drop-weight. This is essential for detecting Barely Visible Impact Damage (BVID).
• ISO 15024: Specifically focuses on Mode I interlaminar fracture toughness, measuring the energy required to "peel" layers apart.

Testing Requirements
Most of these tests require a Universal Testing Machine (UTM) equipped with high-accuracy load cells and strain measurement tools (extensometers or strain gauges).

• Fiberglass: Typically requires 30 kN to 50 kN systems.
• Carbon Fiber: Often requires higher capacity systems (100 kN to 300 kN) due to the material's superior strength.

Average Cost of Destructive Composite Testing (2026 Estimates)

Test Method	Standard	Complexity	Setup Fee (Est.)	Price per Specimen (Est.)
Tensile	ASTM D3039	Moderate	$500 - $800	$150 - $350
Compression	ASTM D6641	High	$600 - $950	$250 - $450
Short-Beam Shear	ASTM D2344	Low	$300 - $500	$80 - $150
Flexural (Bending)	ASTM D7264	Moderate	$450 - $700	$120 - $280
Impact (Drop Weight)	ASTM D7136	Very High	$900 - $1,500	$400 - $700
V-Notch Shear	ASTM D5379	High	$700 - $1,100	$300 - $550

Below is a list of testing facilities located in proximity to key team clusters as of 2026.

1. Texas (The Primary Hub)

• Composites Universal Group (CUG): Located in Dallas, TX, they offer carbon fiber and fiberglass manufacturing and testing, specifically tailored for aerospace and automotive sectors.
• Alpine Polytech / Alpine Advanced Materials: Based in Dallas and Flower Mound, TX, these labs specialize in advanced materials and forensic testing of polymers and composites.
• Advanced Composites Laboratory at Texas State University: Located in San Marcos, TX, providing academic and industrial support for composite testing and R&D.
• Kleinfelder's Dallas Laboratory: A high-capacity laboratory specialized in materials testing for large-scale infrastructure and industrial projects.

2. California (Los Angeles & Orange County)

• Element U.S. Space & Defense: Their Fullerton, CA laboratory is a massive facility offering mechanical and environmental testing for composites.
• Applied Composites: Located in Los Alamitos and San Diego, CA, providing end-to-end manufacturing and structural testing services.
• Rock West Composites: Based in San Diego/Santa Ana areas, they provide dedicated material and structural testing for composite hardware.
• CE-CERT at UC Riverside: While primarily for vehicle emissions, they operate advanced vehicle testing laboratories suitable for performance analysis of battery-electric and hybrid vehicles.

• Kentucky (Paintsville/Lexington): Teams here can possibly leverage university-affiliated labs at the University of Kentucky or regional aerospace testing centers.
• Pacific Northwest (Oregon/Washington): Fatigue Technology (FTI): Based in Seattle, WA, they are specialists in fatigue and fracture testing for composite materials.
• Michigan (Detroit/Ann Arbor Area): Element Materials Technology: Multiple locations in Michigan that provide standardized ASTM/ISO destructive testing for the automotive supply chain.

Appendix Information provided by Lucas Kiowski, Iron Lions Solar Car Team, Greenville, Texas.

Attachments:
Destructive Test Analysis presented by the Seattle Solar Car Team

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