Thick Fiber-Reinforced Composite Laminate for Crack Resistance
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Solution Overview
Problem
Carbon fiber-reinforced sheet molding compounds (CF-SMC) are prone to internal cracks and poor release properties due to thermal expansion and contraction differences between materials during compression molding, especially in thick portions, leading to molding failures like internal cracks and deformation.
Innovation Solution
A fiber-reinforced composite material molded article is produced using a laminate structure with an inner layer of epoxy resin-based composite material (A) and a surface layer of vinyl ester resin-based composite material (B), optimizing the thickness ratio and composition to inhibit internal cracks and enhance release properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If CF-SMC is used for compression molding of thick portions, then thermal conductivity and strength are improved, but internal cracks occur due to thermal expansion and contraction differences
Solution Approach 1:
The invention uses a composite structure combining CF-SMC (carbon fiber-reinforced sheet molding compound) and thermoplastic resin in a layered configuration. The CF-SMC layer provides high strength and thermal conductivity, while the thermoplastic resin layer acts as a buffer to accommodate thermal expansion and contraction differences, preventing internal cracks during compression molding of thick portions.
2Strength
If CF-SMC is used for compression molding, then mechanical characteristics are improved, but release properties deteriorate due to high stiffness
Solution Approach 1:
The invention creates a composite molded article with CF-SMC and thermoplastic resin layers. The thermoplastic resin layer has different thermal and mechanical properties that facilitate easier release from the mold during compression molding, while the CF-SMC layer maintains the required high mechanical characteristics. This composite approach allows the article to be successfully removed from the mold without compromising structural integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively inhibits internal cracks and improves release properties, making the composite material suitable for thick portions and complex shapes, suitable for applications requiring high strength and stiffness, such as automotive components.
Implementation Method 1
the thick portion tends to be affected by thermal expansion resulting from heating, thermal contraction resulting from cooling
Implementation Method 2
the thick portion tends to be affected by thermal expansion resulting from heating, thermal contraction resulting from cooling
Implementation Method 3
the heating resulting from a curing reaction
Data Source
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AI summary
Provided is a fiber-reinforced composite material molded article including a thick portion having a thickness equal to or greater than 10 mm, in which the thick portion has an inner layer which is formed of a cured material of a composite material (A) containing reinforcing fiber and an epoxy resin and a surface layer which is formed of a cured material of a composite material (B) containing reinforcing fiber and a vinyl ester resin.