unibody

mechanics

Also known as: unit body

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Last updated

July 20, 2026

Quick Summary

A unibody is a single structural unit in an automobile that combines the chassis and body into one component. This construction method emerged from the demand for lighter, more fuel-efficient vehicles.1

In contrast to older body-on-frame construction, where the body was attached to a separate chassis, unibody designs use a reinforced steel body shell as the primary structural element. This approach helps to absorb energy during impacts and can limit intrusion in accidents. Modern unibody construction contributes to overall vehicle weight reduction, which is crucial for improving fuel economy.21

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automobile
Chassis
…this arrangement, called unit-body (or unibody) construction, the steel body shell is reinforced with braces that make it rigid enough to resist the forces that are applied to it. Separate frames or partial “stub” frames have been used for some cars to achieve better noise-isolation characteristics. The heavier-gauge steel present…
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…this arrangement, called unit-body (or unibody) construction, the steel body shell is reinforced with braces that make it rigid enough to resist the forces that are applied to it. Separate frames or partial “stub” frames have been used for some cars to achieve better noise-isolation characteristics. The heavier-gauge steel present…
Read More