Pultrusion vs. RTM what's the difference?

Robert Glass

Head of Marketing

Reading time: 4 minutes

Unraveling the strength showdown

Tensile properties of pultruded and pull-wound fiberglass and carbon fiber composite profiles vs. aluminum

In the world of materials engineering, the quest for stronger, lighter, and more durable materials has led many in the direction of composites. Two prominent contenders in this arena are pultruded and pull-wound fiberglass and carbon fiber composite profiles, which are often pitted against traditional aluminum profiles. This blog delves into the mechanical properties of tensile strength, comparing these materials and highlighting their unique characteristics.

Tensile strength: the basics

Tensile strength is a fundamental mechanical property that measures a material’s ability to withstand pulling forces without breaking or deforming permanently. In applications where structural integrity is crucial, like aerospace, automotive, and construction, tensile strength is a constant consideration.

Pultruded and pull-wound fiberglass and carbon fiber profiles

Pultrusion is a manufacturing process where continuous unidirectional (UD) glass or carbon fibers are impregnated with a thermosetting resin, typically polyester, vinylester, or epoxy. The resulting profiles exhibit exceptional strength-to-weight ratios, making them an ideal choice for lightweight and high-strength applications. Pultruded fiberglass profiles boast impressive tensile strength, outperforming many metals, including aluminum. Their corrosion resistance makes them highly suitability for harsh environments. Pull-winding is similar to pultrusion with the addition of cross-would fibers (helically) around the profile, in addition to UD fiber alignments. This produces profiles with exceptional strength, stiffness, and low weight, making them highly sought-after in aerospace, sports equipment, and high-performance automotive industries. Carbon fiber composite profiles demonstrate remarkable tensile strength, surpassing aluminum while also possessing excellent fatigue resistance.

Comparing with similar aluminum profiles

Aluminum profiles

Aluminum has been a go-to material for various engineering applications due to its moderate strength, low density, and excellent corrosion resistance. However, when it comes to tensile strength, both pultruded fiberglass and carbon fiber composite profiles have the upper hand.

Tensile Strength Comparison

In head-to-head comparisons, pultruded fiberglass profiles typically exhibit similar or marginally higher tensile strength than their aluminum counterparts. However, it’s their higher specific tensile strength (tensile strength per unit weight) that sets them apart, making them a favored option in weight-sensitive industries.

On the other hand, carbon fiber composite profiles boast significantly higher tensile strength compared to aluminum profiles. This allows engineers to design structures with reduced weight and increased load-bearing capacity, leading to improved performance and fuel efficiency in aerospace and automotive applications.

Pultruded and pull-wound fiberglass and carbon fiber composite profiles showcase remarkable tensile strength, outperforming traditional aluminum profiles in various applications. Both materials have revolutionized the engineering landscape, enabling the development of lighter, stronger, and more efficient structures across industries. As technology and manufacturing processes advance, these composite materials are expected to play an increasingly pivotal role in shaping the future of engineering and design.

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