Verbindungen von Sandwichelementen unter kombinierter Längs‐ und Querkraftbeanspruchung

Abstract

Sandwichelemente werden über Verbindungsmittel, meist selbstbohrende Schrauben, an eine Unterkonstruktion montiert. Diese raumabschließenden Bauteile sind sowohl Beanspruchungen senkrecht zur Elementebene als auch durch Belastungen in der Ebene ausgesetzt, z. B. durch das Eigengewicht der Wandelemente. Über die Verbindungsmittel werden Längszugkräfte und Querkräfte vom Bauteil in die Unterkonstruktion weitergeleitet. Für die kombinierte Beanspruchung von Längs‐ und Querkräften liegen zurzeit noch keine experimentellen und theoretischen Untersuchungen zur Tragfähigkeit der Verbindung vor. Anhand von Versuchen und einem mechanischen Modell wird das Tragverhalten von längs‐ und querkraftbeanspruchten Verbindungen von Sandwichelementen im Folgenden analysiert. Fastenings of sandwich panels under combined longitudinal and shear load. Sandwich panels are mounted by fasteners, usually self‐drilling screws, to a substructure. These space‐enclosing components are stressed perpendicularly to the panel surface and in wall‐elements by loads in their plane (by self‐weight). The tensile and transverse forces are transmitted from the panel into the substructure by fasteners. Up to now the interaction of longitudinal and transverse forces in the connection has not been assessed by any experimental or theoretical study. On the basis of experiments and a mechanical model the structural behavior of fasteners of sandwich panels loaded by longitudinal and transverse forces will be analyzed in the following.

Resistance of Direct Fixings of Sandwich Panels under Cyclic Loading

“…Failure occurs when the ultimate strain in the tensile ring is reached (6). For direct fixings, the screw is fully screwed through the panel into the substructure, penetrating both face sheets and the core layer.…”

“…1. Pull-through failure on the left, small scale specimen on the right (5) Failure occurs when the ultimate strain in the tensile ring is reached (6). This results in a starshaped crack pattern with uniformly distributed cracks at the edge of the hole (Fig.…”

“…Due to the small bending stiffness of the thin face sheets, a rotational symmetrical membrane state of stress with a tangential tension and compression ring and radial tensile stresses occur around the borehole. Failure occurs when the ultimate strain in the tensile ring is reached (6). This results in a starshaped crack pattern with uniformly distributed cracks at the edge of the hole (Fig.…”