Influence of the fibre orientation on the lap shear strength and fracture behaviour of adhesively bonded composite metal joints at high strain rates

2020 ◽  
Vol 97 ◽  
pp. 102486 ◽  
Author(s):  
H. Grefe ◽  
M.W. Kandula ◽  
K. Dilger
Keyword(s):  
Shear Strength ◽  
High Strain ◽  
Fracture Behaviour ◽  
Fibre Orientation ◽  
Strain Rates ◽  
Adhesively Bonded ◽  
High Strain Rates ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Bonded Composite

Effect of aluminium substrate thickness on the lap-shear strength of adhesively bonded and hybrid riveted-bonded joints

2020 ◽  
pp. 095440892091343
Author(s):  
VC Beber ◽  
N Wolter ◽  
B Schneider ◽  
K Koschek
Keyword(s):  
Shear Strength ◽  
Failure Process ◽  
Lap Joints ◽  
Substrate Thickness ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Definition Of ◽  
Structural Adhesive

For lightweight materials, e.g. aluminium, the definition of proper joining technology relies on material properties, as well as design and manufacturing aspects. Substrate thickness is especially relevant due to its impact on the weight of components. The present work compares the performance of adhesively bonded (AJ) to hybrid riveted-bonded joints (HJ) using aluminium substrates. To assess the lightweight potential of these joining methods, the effect of substrate thickness (2 and 3 mm) on the lap-shear strength (LSS) of single lap joints is investigated. An epoxy-based structural adhesive is employed for bonding, whilst HJs are produced by lockbolt rivet insertion into fully cured adhesive joints. The stiffness of joints increased with an increase of substrate thickness. HJs presented two-staged failure process with an increase in energy absorption and displacement at break. For HJs, the substrate thickness changed the failure mechanism of rivets: with thicker substrates failure occurred due to shear, whereas in thinner substrates due to rivet pulling-through. The LSS of 2 mm and 3 mm-thick AJs is similar. With 2 mm-thick substrates, the LSS of HJs was lower than AJs. In contrast, the highest LSS is obtained by the 3 mm-thick HJs. The highest lightweight potential, i.e. LSS divided by weight, is achieved by the 2 mm-thick AJs, followed by the 3 mm-thick HJs with a loss of ca. 10% of specific LSS.

Effects of High Strain Rates on Ductile Slant Fracture Behaviour of Pipeline Steel: Experiments and Modelling

2016 ◽  
Author(s):  
Reza Hojjati ◽  
Matthias Steinhoff ◽  
Steven Cooreman ◽  
Filip Van den Abeele ◽  
Patricia Verleysen
Keyword(s):  
Ductile Fracture ◽  
High Strain ◽  
Fracture Behaviour ◽  
Pipeline Steel ◽  
Numerical Approach ◽  
Strain Rates ◽  
High Strain Rates ◽  
X70 Pipeline Steel ◽  
Split Hopkinson Tensile Bar ◽  
Split Hopkinson

Good material properties are required to ensure the safe and reliable design of oil and gas transmission pipelines. The main objective of the study, presented in this paper, is to examine the influence of high strain rates on the hardening and ductile fracture behaviour of an API 5L X70 pipeline steel by means of a combined experimental/numerical approach. For this purpose, the impact toughness of the material is assessed using instrumented Charpy V-notch (CVN) impact tests at a wide range of temperatures. To characterize the mechanical response of an X70 pipeline steel subjected to high strain rates, split Hopkinson tensile bar (SHTB) experiments are performed. These experiments allow deriving the true effective stress versus plastic strain, strain rate and temperature. Both the CVN and SHTB tests results are used for fundamental material research and constitutive material modelling. For the numerical simulations, the modified Bai-Wierzbicki (MBW) model is applied. The MBW model represents the influence of the stress state on the plastic behaviour and the onset of damage, and quantifies the microstructure degradation using a dissipation-energy based damage evolution law. The model hence allows for an accurate prediction of the ductile fracture mechanisms. The combined experimental/numerical approach is then used to simulate the upper shelf ductile fracture behaviour of an API X70 pipeline steel for high strain rate and Charpy tests. Based on the available experimental data, a new parameter set has been determined. Using these new material parameters, good correlations between numerical simulations and experimental observations have been obtained for both the split Hopkinson tensile bar tests and the Charpy impact tests.

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