Search

Your search keyword '"damage velocity"' showing total 4 results
Start Over Descriptor "damage velocity"
4 results on '"damage velocity"'

1. A family of models of hard and soft interfaces with damage.

Author

Lebon, Frédéric, Raffa, Maria Letizia, and Rizzoni, Raffaella

Subjects
*ADHESIVE joints, *STRESS concentration, *ELASTICITY, *AUTOMOTIVE engineering, *ADHESIVES, *BIOMEDICAL engineering
Abstract

In many industrial applications in aeronautical, civil, energetic, automotive and biomedical engineering, adhesion techniques have recently emerged as assembly procedures alternative to conventional joining. Adhesive bonding is advantageous for many aspects, such as mitigation of stress concentration, better resistance to corrosion and water sealing, and the possibility of assembly dissimilar materials. In the literature, interface models are a classical modeling approach to the description of the mechanical behavior of adhesive joints. In this paper, an original generalized interface model is presented for both soft and hard adhesives, characterized by lower and higher stiffness than the adherents, respectively. The proposed model is able to capture a damaging behavior of the adhesive material, the elastic properties of which are obtained by homogenizing a microcracked media. The cracks density in the adhesive is the damage parameter, and a kinetic law based on the generalized standard material model describes its evolution. The role and relevance of damage velocity is illustrated through some simple examples and with a comparison with experimental data taken from literature. The numerical results show how the mechanical properties of the adhesive and the joint degrade as damage evolves, indicating a transition from quasi-brittle to brittle behavior as the damage velocity decreases. • An interface model is presented, for both soft and hard damaging adhesives. • The effect of the damage velocity is introduced. • A quasi-brittle to brittle transition emerges as the damage velocity decreases. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

2. Penetration and failure of lead and borosilicate glass against rod impact

Author

Behner, Th., Anderson, C.E., Orphal, D.L., Hohler, V., Moll, M., and Templeton, D.W.

Subjects
*SPEED, *RADIOGRAPHY, *X-rays, *SCIENTIFIC method
Abstract

Abstract: This paper presents the experimental design and results for gold rod impact on DEDF (5.19g/cm3) and Borofloat (2.2g/cm3) glass by visualizing simultaneously failure propagation in the glass with a high-speed camera and rod penetration with flash radiography. At a given impact velocity, the velocity of the failure front is significantly higher during early penetration than during steady-state penetration of the rod. For equal pressures but different stress states, the failure front velocities determined from Taylor tests or planar-impact tests are greater than those observed during steady-state rod penetration. The ratio of average failure front velocity to rod penetration velocity decreases with increasing impact velocity (v p) in the range of v p=0.4–2.8km/s. As a consequence, the distance between the rod tip and the failure front is reduced with increasing . The Tate term R T increases with impact velocity. [Copyright &y& Elsevier]

Published
2008
Full Text
View/download PDF

3. Stoßwelleninduzierte Risse und Zerstörungen in Gläsern

Author

Straßburger, E., Senf, H., Rothenhäusler, H., and Publica

Subjects
Nukleationsschwelle, Rißzentren, nucleation, Rißgeschwindigkeit, Nukleation, crack velocity, damage velocity, Zerstörungsgeschwindigkeit, Glas, crack centers, nucleation threshold, impact, Glass, Impakt
Abstract

Für vier verschiedene Glassorten (K5, F6, SF6 und Floatglas) mit unterschiedlichen physikalischen Eigenschaften wurden die Ausbreitung von Wellen und Zerstörungen bei Impakt mit zylindrischen Stahlprojektilen qualitativ und quantitativ untersucht. Die Zerstörungsgeschwindigkeiten wurden als Funktion der Impaktgeschwindigkeit gemessen und die Nukleationsschwellen bestimmt. Alle vier Gläser zeigen ein ähnliches Verhalten. Die Zerstörung der Proben erfolgt bei niedrigen Belastungen mit maximaler Rißgeschwindigkeit, bei Einsetzen der Nukleation mit transversaler Wellengeschwindigkeit Ct und bei sehr hohen Belastungen mit longitudinaler Wellengeschwindigkeit CL. Dieses Verhalten wurde unabhängig von der Dicke der Proben beobachtet. Ein funktionaler Zusammenhang zwischen der Nukleationsschwelle (sowohl bezüglich der Impaktgeschwindigkeit als auch bezüglich des Impulses, der von der Druckwelle pro Zeiteinheit auf das Target übertragen wird) und der Dicke der Platten konnte nicht festgestellt werden. Die dargestellten Untersuchungen beziehen sich auf die Zerstörung des Targets von dem Eindringen des Projektils. The propagation of waves and damage at impact of cylindrical steel projectiles was investigated qualitatively and quantitatively for four different types of glass (K5, F6, SF6 and float glass). The damage velocities were measured as a function of impact velocity and the threshold for the nucleation of cracks were determined. All four glasses reveal a similar behaviour. The damage velocity equals terminal crack velocity at low loadings, rises to transversal wave velocity when nucleation occurs and approaches longitudinal wave velocity with very high loadings. This behaviour was observed independent of the thickness of the target plates. A functional relation between the thickness of the plates and the threshold of nucleation could not be established, neither with respect to impact velocity nor with respect to the momentum transferred to the target by the pressure wave . The investigations reported here refer to the damage before the projectile penetrates the target.

Published
1993

4. Propagation of fracture and damage phenomena in glasses at high dynamic loadings

Author

Senf, H., Rothenhäusler, H., Straßburger, E., and Publica

Subjects
optical glass, Zerstörungsgeschwindigkeit, optisches Glas, nucleation, Rißzentrum, impact, Rißgeschwindigkeit, Hochgeschwindigkeitsfotografie, high-speed photography, Impakt, damage velocity, terminal crack velocity
Abstract

Four different types of glasses (float glass, optical glasses K5, F6, SF6) were impacted by pointed and blunt projectiles of different diameters within a velocity range from 10 m/s up to 1600 m/s. The propagation of fractures was observed by means of a 24-spark high-speed camera in a shadow-optical arrangement. In addition to the fractures generated at the impacted edge of the glass slabs, crack nuclei were activated by the longitudinal shock wave if the transferred energy was sufficiently high. All types of cracks observed propagated with terminal crack velocity. In order to describe the damage of the targets by the different phenomena, the concept of damage velocity was introduced. Furthermore, a calibre independent representation of the results was found. The fracture and damage velocities in optical glasses with wave speeds between 4500 m/s and 6000 m/s and densities in the range from 2.5 g/cbcm to 5.2 g/cbcm were determined and compared to the results with float glass.

Published
1992

Catalog

Books, media, physical & digital resources
See catalog results