an epoxy resin was modified by silica nanoparticles and cured with an anhydride. the particles with different batches of 12, 20, and 40 nm sizes were each distributed into the epoxy resin ultrasonically. electron microscopy images showed that the silica particles were well dispersed throughout the resin. tensile test results showed that young’s modulus and tensile strength increased with the vo...

Mechanical behaviour of unsaturated polyester resin used for the composite materials has been studied to determine various important parameters, such as tensile and compressive, single edge-notch tensile fracture toughness, flexural properties and fracture energy. Fracture toughness, KIC, and fracture energy, GIC, obtained for the polyester resin lie between the typical values for epoxy resins ...

Seed size and toughness affect seed predators, and size-dependent investment in mechanical defence could affect relationships between seed size and predation. We tested how seed toughness and mechanical defence traits (tissue density and protective tissue content) are related to seed size among tropical forest species. Absolute toughness increased with seed size. However, smaller seeds had high...

In this letter we present the "Egg of Columbus" for making fibres with unprecedented toughness: a slider, in the simplest form just a knot, is introduced as frictional element to dissipate additional energy and thus demonstrating the existence of a previously "hidden" toughness. The proof of concept is experimentally realized making the world's toughest fibre, increasing the toughness modulus o...

The toughness of Fe-based bulk metallic glasses BMGs has been significantly improved via systematic changes in chemistry. Chemistry changes were selected based on their likely effects on critical elastic constants shown to affect plasticity/toughness in various BMGs, in addition to their recently discovered effects on chemical bonding in these Fe-based systems. The fracture energy obtained on n...

This study examined the association between goal orientations and mental toughness and its influence on performance outcomes in competition. Wushu athletes (n = 40) competing in Intervarsity championships in Malaysia completed Task and Ego Orientations in Sport Questionnaire (TEOSQ) and Psychological Performance Inventory (PPI). Using cluster analysis techniques including hierarchical methods a...

This paper investigates the interaction between cutting tool edge radius and material separation due to ductile fracture based on Atkins’ model of machining. Atkins’ machining model considers the energy needed for material separation in addition to energies required for shearing at the primary shear zone and friction at the secondary shear zone. However, the effect of cutting tool edge radius, ...

This paper investigated the effects of combining fibers with self-consolidating concrete (SCC). 12 series of test specimens were prepared using three kinds of fibers including steel, polyphenylene sulfide (PPS) and glass fibers with four different volumes fractions and one specimen without fibers as a reference sample. All plans were subjected to fresh concrete tests. For mechanical behavior of...

The welding heat input has a great influence on the weldments properties. This paper describes the influence of welding heat input on the weld metal toughness of high-carbon steel surface welded joint. The steel is surfaced with self-shielded wire, with three different heat inputs (6.5; 10.5 and 16 kJ/cm). Total impact energy, as well as crack initiation and crack propagation energies, are esti...

This paper reports results of in-house experimentation on heat treatment and mechanical testing of H13 tool steel. Heat treatment strategy practiced by the industry is described in detail. Effect of various types of heat treatment on fracture toughness, hardness and other mechanical properties is also analyzed. It was found that toughness (expressed in terms of plane-strain fracture toughness K...