Purpose The purpose of this paper is to study the potential of alumina (Al2O3) in nanometer size in automotive brake friction materials. Design/methodology/approach Four brake linings containing alumina differing in particle size (355 µm and 80 nm) and various amount (5 and 10 Wt.%) were designed and produced. The hardness, density and porosity of the samples were measured. All samples were tested on a full-scale brake dynamometer with gray cast iron disc to determine the tribological properties. Detailed examinations on the worn surface were analyzed using a scanning electron microscopy. Findings It was concluded that all performance parameters were beneficially affected because of nano alumina. Originality/value This paper emphasizes the importance of nano-composites in the automotive industry and helps industrial firms and academicians working on wear of materials.

Purpose – Among the components used for a car brake lining, the chemical and structural properties of the abrasives, jointly with the morphology and size of the particles influence the friction parameters and stability of the composite. This paper aims to investigate the effect of nano SiO2 particles in brake pads on friction and wear properties. Design/methodology/approach – In this paper, the effects of SiO2 (Silica) particles of varying size on the friction-wear properties of polymeric friction composites are investigated. Four friction composites were prepared containing (5, 10 Wt.%) micro silica (MS) particles and (5, 10 Wt.%) nano silica (NS) particles. The samples were produced by a conventional procedure for a dry formulation following dry-mixing, pre-forming and hot pressing. Friction and wear characteristics of the specimens against to a disk made of cast iron were studied. Friction coefficient, specific wear rate and hardness of specimens were obtained. Detailed examinations on the worn surface were analyzed using a scanning electron microscope. Findings – The results of test showed that the inclusion of nano silicon carbide (SiC) powder improved the wear performance significantly. Friction coefficient (μ) of NS samples was higher than the MS samples. Micro-SiC showed poor performance and μ. High wear performance was exhibited in materials containing 5 Wt.% NS and 10 Wt.% NS. Originality/value – This paper emphasizes the importance of nano-composites in the automotive industry and helps to industrial firms and academicians working on wear of materials.

Thermal buckling analysis of symmetric and antisymmetric laminated composite plates with clamped and simply supported edges, and containing a hole is presented in this paper. The first-order shear deformation theory in conjunction with the variational energy method is employed in mathematical formulation. The eight-node Lagrangian finite element technique is used to find thermal buckling temperatures of isotropic, glass-epoxy and boron-epoxy laminates. The effects of hole size, angle of ply orientation, lay-up sequences, and boundary conditions on thermal buckling temperatures are investigated. The result is shown in graphical forms for various boundary conditions.

An elastic-plastic stress analysis is carried out in a thermoplastic composite cantilever beam loaded by a bending moment at the free end. The orientation angle is chosen as 0°, 15°, 30°and 45°. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli-Navier hypotheses. It is found that the intensity of the residual stress component s x is maximum at the upper and lower surfaces. The beam material is assumed to be strain-hardening. The Tsai-Hill theory is used as a yield criterion. The displacement components are found in the elastic region.

This study investigated the effects of composite repair patches and number of patch layers on the fatigue behavior of surface-notched composite pipes. The pipes were repaired using glass/epoxy composite patches of two to seven layers. Failure modes were examined and S-N curves were plotted. Fatigue tests showed that the fatigue life of the repaired pipes was improved by increasing the number of patch layers. The seven-layer composite patch was most effective in preventing fatigue failure and increasing the fatigue life of the surface-notched pipes.