No abstract

A fracture mechanics model is proposed to describe fatigue crack propagation in notched specimens. This model accounts for residual stresses which are present at the notch root after unloading from maximum compressive load. This is of particular interest for specimens subjected to compressive mean load. According to the model, cracks will stop growing at the boundary of the plastically deformed zone if the specimen is subjected to compressive load only. Validity of the model was verified with notched specimens of mild steel.

No abstract

Experimental investigations and parametric finite element analyses show that the moment‐rotation characteristic of sandwich panels providing support against the lateral torsional buckling of beams subjected to gravity loading can be represented as tri‐linear. Formulae for calculating the parameters of this characteristic are given for different types of beam combined with sandwich panels for roofs and walls. According to available design codes, the torsional restraint coefficient for rotational stiffness cϑ required for design against lateral torsional buckling of beams is governed by the rotational stiffness cϑA of the connection, which can be obtained from the characteristic mentioned as the secant stiffness for all common types of sandwich panel and different types of structural arrangement. These values allow the maximum spans of beams to be increased and help to improve the economy of lightweight structures.

Entstehung und Hintergründe der im Stahlbau bis heute bewährten Regeln zur Absicherung gegen Sprödbrüche stehen am Anfang dieser Übersicht. In der Folge ist parallel zur Entwicklung bruchmechanischer Methoden eine enorme Verbesserung der Zähigkeitseigenschaften der Stähle zu sehen. Beides findet seinen Niederschlag in Entwürfen für die Empfehlungen zur Stahlauswahl. Dazu liegt ein Vergleich mit den bestehenden Regeln nahe, wobei auch über Versuchsergenisse zu berichten ist.