Sandwich Core Structural Element with Hot-Wire Cut Surface
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Solution Overview
Problem
Existing structural elements for sandwich composite elements, particularly in wind blades and marine applications, face challenges in reducing resin absorption while maintaining adhesive strength, leading to increased weight and density, and existing solutions either compromise adhesion or increase manufacturing complexity.
Innovation Solution
The structural element is produced with a surface optimized by hot element cutting, creating open pores for resin anchoring while partially sealing to reduce resin absorption, using a process that controls temperature and feed rate to achieve a gloss value between 2 and 10, ensuring good adhesion and low resin absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the foam is made more fine-pored to reduce resin absorption, then resin absorption is reduced, but adhesion between structural element and cover layer becomes insufficient
Solution Approach 1:
The patent applies local quality by creating two distinct surface zones: a first zone with closed or partially closed pores for low resin absorption, and a second zone with open pores for good adhesion. This spatial differentiation of pore structures allows each zone to fulfill its specific function independently, resolving the contradiction between reducing resin absorption and maintaining adhesion.
2Loss of substance
If the foamed material is compacted using pressure and temperature to reduce resin absorption, then resin absorption is reduced, but manufacturing complexity and cost increase due to additional work steps
Solution Approach 1:
The patent applies preliminary action by creating the differentiated pore structure during the initial foaming and cutting process, rather than requiring subsequent compaction steps. The hot element cutting process simultaneously performs cutting and creates the desired surface pore structures, eliminating the need for separate pressure and temperature treatment steps.
3Ease of manufacture
If sawing is used to divide the foam block into structural elements, then manufacturing is simple, but the surface becomes highly porous leading to high resin absorption
Solution Approach 1:
The patent replaces the mechanical sawing system with a hot element cutting system. The hot element (wire or blade) melts and seals the foam material during cutting, simultaneously achieving separation of structural elements and creation of low-porosity surfaces. This substitution eliminates the high porosity problem inherent in mechanical sawing while maintaining manufacturing efficiency.
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
This approach results in a structural element with reduced resin absorption and maintained adhesive strength, achieving a lower overall weight with equivalent mechanical load capacity, suitable for load-bearing applications in lightweight construction.
Implementation Method 1
hot element cutting, the surface of the first surface side (1) being created in such a way that open pores (6) are present
Implementation Method 2
hot element cutting, creating open pores for resin anchoring while partially sealing
Implementation Method 3
hot wire or hot cutting blade to separate the structural element from the foam block, thereby thermally sealing the surface
Implementation Method 4
open pores which ensure the desired anchoring of the resin in the structural element
Implementation Method 5
open pores (6) are present, which ensure the desired anchoring of the resin in the structural element (2)
Data Source
Figure 1~3
Figure 4~8
Figure 9~11
AI summary
The invention relates to a structural element for use as a core layer in a sandwich composite element, wherein the structural element (2) is made of multiple body segments (4, 5) welded to each other, which body segments are made of an extrusion-foamed thermoplastic plastic, in particular PET, and wherein the structural element (2) has a first face side (1) for adhesively bonding to a covering layer, wherein a surface of the first face side (1) to which a resin (8) can be applied has open pores (6). Furthermore, the surface of the first face side (1) is produced by heating-element cutting, in particular heating-wire cutting, in such a way that the surface is partially thermally sealed.