4 Mechanical characterization on constituent level
In composite sandwich construction, three main constituents are of primary interest on
constituent level. These include core, face sheets and adhesives. In case plastics are used
for load introduction elements, such as inserts, these materials may be also of interest
on constituent level. Additionally, used metallic elements are usually the strongest component in sandwich construction. Therefore, they do not require a detailed analysis. In
addition, elastic material properties are readily available for common metals. This chapter describes the mechanical characterization of the relevant constituents in the framework of the present thesis.
4.1 Sandwich core
The two most important mechanical properties of the core are its transverse shear and
out-of-plane compressive resistance. These are also the properties that are typically
given by core manufacturers. For detailed analyses of sandwich joints, the out-of-plane
tensile properties may be additionally of interest. Honeycomb cores have generally very
low in-plane mechanical properties. Hence, they do not contribute to the overall in-plane
strength of a sandwich panel and it is common practice to make assumptions regarding
the in-plane properties rather than doing additional tests. Therefore, there are three
tests that are of particular interest for the mechanical characterization of the core –
transverse shear, flatwise compression and flatwise tension. In the performed experimental study, structural tests were only conducted on cured honeycomb cores. Additional tests on the core constituents Nomex and phenolic resin were left out for different
reasons. Firstly, in the framework of the present thesis the macroscopic core behavior is
of primary interest. Therefore, assumptions for the mechanical behavior of its constituents are tolerable, as long as the macroscopic behavior is predicted accurately. Another
aspect is the accessibility of the base materials. Core manufacturers generally do not
disclose details of their fabrication processes, making it difficult to acquire comparable
sets of the constituents. In addition, there are some studies available in literature, which
© Springer-Verlag GmbH Germany, part of Springer Nature 2020
R. Seemann, A Virtual Testing Approach for Honeycomb Sandwich Panel
Joints in Aircraft Interior, Produktentwicklung und Konstruktionstechnik 16,
https://doi.org/10.1007/978-3-662-60276-8_4
In composite sandwich construction, three main constituents are of primary interest on
constituent level. These include core, face sheets and adhesives. In case plastics are used
for load introduction elements, such as inserts, these materials may be also of interest
on constituent level. Additionally, used metallic elements are usually the strongest component in sandwich construction. Therefore, they do not require a detailed analysis. In
addition, elastic material properties are readily available for common metals. This chapter describes the mechanical characterization of the relevant constituents in the framework of the present thesis.
4.1 Sandwich core
The two most important mechanical properties of the core are its transverse shear and
out-of-plane compressive resistance. These are also the properties that are typically
given by core manufacturers. For detailed analyses of sandwich joints, the out-of-plane
tensile properties may be additionally of interest. Honeycomb cores have generally very
low in-plane mechanical properties. Hence, they do not contribute to the overall in-plane
strength of a sandwich panel and it is common practice to make assumptions regarding
the in-plane properties rather than doing additional tests. Therefore, there are three
tests that are of particular interest for the mechanical characterization of the core –
transverse shear, flatwise compression and flatwise tension. In the performed experimental study, structural tests were only conducted on cured honeycomb cores. Additional tests on the core constituents Nomex and phenolic resin were left out for different
reasons. Firstly, in the framework of the present thesis the macroscopic core behavior is
of primary interest. Therefore, assumptions for the mechanical behavior of its constituents are tolerable, as long as the macroscopic behavior is predicted accurately. Another
aspect is the accessibility of the base materials. Core manufacturers generally do not
disclose details of their fabrication processes, making it difficult to acquire comparable
sets of the constituents. In addition, there are some studies available in literature, which
© Springer-Verlag GmbH Germany, part of Springer Nature 2020
R. Seemann, A Virtual Testing Approach for Honeycomb Sandwich Panel
Joints in Aircraft Interior, Produktentwicklung und Konstruktionstechnik 16,
https://doi.org/10.1007/978-3-662-60276-8_4