Simulating brittle and ductile response of alumina ceramics under dynamic loading

Alumina ceramic is often used in armour systems. This material is known to have a brittle response under tensile loading, while a ductile response is found when sufficiently high pressures are reached. During projectile impact a ceramic material experiences both tensile loading and high pressures, hence fails in both a brittle and ductile way....

Scaling of pop-ins during brittle fracture testing

Measurement of the fracture toughness of steel is important for the assurance of the safety of ships and offshore structures, especially when these structures are made of thick sections and/ or applied in cold environments. One key factor that will affect the determination of the fracture toughness is a pop-in, which is a short event in which...

Dynamic simulations of traditional masonry materials at different loading rates using an enriched damage delay: Theory and practical applications

Modelling the mechanical response of adobe components under uniaxial loading

An approach to using Weibull stress analysis in design

Current codes and norms allow for structures to be operated in the transition between ductile and brittle behavior. Further, they often treat the Ductile to Brittle Transition Temperature as a constant even though it is well known to depend on a variety of factors, such as loading rate, constraint, and prior cold deformation. This paper roposes...

Relating structural loading rate to tensing rate for fracture mechanics specimens

It is vely well-known that fracture toughness depends on loading rate. Higher strain rates can shift the ductile to brittle transition curve to higher temperatures, resulting in a more brittle structure at the same temperature. However, there is little effort to relate the testing rate to the loading rate within the offshore and maritime...

Cryogenic crashworthiness of LNG fuel storage tanks

Shipping is gradually embracing natural gas as bunker fuel. The most viable way to store natural gas on board is in its liquid form. Gas needs to be cooled to cryogenic temperatures and in practice moderately pressurized. On board ships, solely double walled pressure tanks are used for this purpose. Loss of containment due to a collision, is one...

Kinetic energy density and agglomerate abrasion rate during blending of agglomerates into powders

Problems related to the blending of a cohesive powder with a free flowing bulk powder are frequently encountered in the pharmaceutical industry. The cohesive powder often forms lumps or agglomerates which are not dispersed during the mixing process and are therefore detrimental to blend uniformity. Achieving sufficient blend uniformity requires...

Ultra-short-pulsed laser-machined nanogratings of laser-induced periodic surface structures on thin molybdenum layers

Large areas of regular diffraction nanogratings were produced consisting of so-called laser-induced periodic surface structures (LIPSS) on thin molybdenum layers (<400 nm) deposited on a borosilicate glass substrate. The aim was to produce these structures without ablating nor cracking the molybdenum layer. Ultra short laser pulses were applied...

Control of relaxation cracking in austenitic high temperature components

The degradation mechanism "relaxation cracking" is acting in austenitic components operating between 550°C (1020°F) and 750°C (1380°F). The brittle failures are always located in cold formed areas or in welded joints and are mostly addressed within 1 year service. More than 10 different names can be found in the literature for this phenomenon. A...

The effect of particle size on fracture properties and size effect of concrete

In the study the effect of scaling the material structure on the fracture behaviour of concrete is investigated. Next to this the size effect of concrete fracture strength and fracture energy is studied. The fracture mechanism of concrete made with different size aggregates are tested numerically. A lattice type fracture model is adopted to...

Probabilistic maintenance planning for the tubular joints in the steel gates in the eastern Scheldt storm surge barrier

This paper is a summary of a study on the tubular joints in the steel gates of the Eastern Scheldt storm surge barrier in the Netherlands. This study was commissioned by the Directorate-General for Public Works and Water Management (Rijkswaterstaat) and carried out in the period 1985-1992. At a late stage during the fabrication of the Eastern...

Environmental stress cracking of PVC and PVC-CPE - Part II Failure mechanisms

The failure of unnotched PVC and PVC-CPE was studied in a number of vapour and liquid environments. The failure mechanisms observed are related to craze initiation and logarithmic craze growth. A model to explain the origin of the logarithmic craze growth is presented. The failure mechanism in air and in benzene and toluene vapours is ductile,...