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The environment is a very important topic today as well as in the future. One source of air pollution that has the potential to harm health is the wear particles released by vehicle braking systems. If these wear particles come from hazardous materials, they could destroy human health and the environment. Based on these conditions, exploring more environmentally friendly materials to substitute hazardous materials as friction materials is necessary. In this study, brake linings were prepared from bamboo fiber and eggshell (ES) particles with various pre-treatment conditions. The composition of the material frictions consisted of phenolic resin, bamboo fiber, bamboo particles, ES particles, zinc, alumina, and graphite in the following: 35% phenolic resin, 10% graphite, 10% bamboo fiber, 10% alumina powder, 5% zinc powder, and 30% bamboo particles and ESs. This study focused on observing the mechanical and tribological behavior of friction materials when using ES particles as fillers. There are three stages to manufacturing friction material: a cold press, a hot press, and heat treatment. The optimization of the characteristics of ESs as organic brake linings was carried out using the Taguchi method and analyzed using data envelopment analysis-based ranking (DEAR). An interesting finding from this study was that when ES particles were calcined at 900°C for 120 min, the ES particle size was 200 mesh, and the ES volume fraction at 25% resulted in the most optimal brake lining performance. Calcination at 900°C for 120 min completely changed the CaCO3 phase to CaO. This study also shows that calcined ES particles have the potential to be developed as friction materials for environmentally friendly two-wheeled vehicles in the future. The produced brake linings exhibited hardness, a coefficient of friction, and specific wear rates of 92.82 HR, 0.32, and 4.43 × 10−6 mm3·N−1·m−1, respectively.

Exposure to a humid environment can affect the behavior of brake lining composites. Considering the vital function of brake linings in controlling vehicle speed, environmental influences must receive serious attention. Exposure to lubricating oil that sticks to the brake lining can cause changes in performance during work. This study will investigate the dimensional stability of brake pad composites when exposed to engine oil and understand the physical behavior of material to facilitate appropriate handling. The brake pads in this study comprised 35% phenolic resin, 10% graphite, 10% bamboo fiber, 10% alumina powder, 5% zinc powder, 5% bamboo particles, and 25% eggshell particles. The manufacturing of brake linings involves three process stages: cold compaction, hot compaction, and post-curing. The samples were soaked in Federal Ultratec API SJ JASO MA engine lubricating oil for 12, 24, 36, and 48 hours. The results showed that the immersion time of the composite in lubricating oil did not significantly affect the dimensional stability of the composite. This result shows that the addition of calcined eggshell particles can improve the material's resistance to engine lubricating oil.

The development of the global economy has led to a rise in ship traffic. As a result, the risk of accidents, such as collisions between ships and grounding, has also increased. Different failure criteria to capture these accidents have been introduced by researchers. Therefore, the purpose of this study was to determine the essential distinction between these failure criteria. The simulations suggest that failure criteria based on the maximum stress result in a slightly higher rupture strain value, greater crack propagation, and higher internal energy than those based on the maximum strain. Furthermore, using a larger mesh size compared with the size of the test specimen appears to greatly affect the validity of the simulation results.

This work aims to investigate the mechanical behavior of steel-plated structures under a raking incident and to quantify the effect of the mesh size in nonlinear finite element (NLFE) analysis. To conveniently comprehend nonlinear phenomena, i.e., the grounding which takes place in this work, a series of theoretical contact formulations was defined. In the main analysis, raking, which is a part of the grounding scenario, was strictly assumed as contact between a tanker, which was assumed to have thin-walled steel, and a seabed rock in the form of a solid obstruction. Designed raking scenarios were calculated using the FE method by using the nonlinear phenomena of the material behavior in the calculation. The findings of this work indicated that the possibility of expanding the recommended mesh size in FE simulation should be evaluated by quantifying the behavior of structural responses, such as energy, the force damage pattern, and acceleration, subjected to a variety of applied meshing techniques. The results concluded that a notable difference occurred when the mesh size was more than 132 mm (ratio 11 based on the plate dimension in this work), and this size is strictly recommended to be used for calculation of the element length-to-thickness (ELT) ratio. Assessment in time simulation showed that applying larger mesh sizes will reduce the simulation time but increase the maximum values of the crashworthiness parameters, i.e., energy, force, acceleration, and displacement.

A research subject in structural engineering is the problem of vibration under a loading object. The two-dimensional (2D) model of a structure under loading is an example. In general, this case uses an object that is given a random frequency, which then causes various changes in shape depending on the frequency model. To determine the difference in performance by looking at the different forms of each mode, modal analysis with ANSYS was used. The samples to be simulated were metal plates with three variations of the model, namely, a virgin metal plate without any holes or stiffness, plates with given holes, and metal plates with stiffness on one side. The model was simulated with modal analysis, so that 20 natural frequencies were recorded. The sample also used different materials: low-carbon steel materials (AISI 304), marine materials (AISI 1090), and ice-class materials (AR 235). Several random-frequency models proved the deformation of different objects. Variations of sheet-metal designs were applied, such as pure sheet metal, giving holes to the sides, and stiffening the simulated metal sheet.

The utilization of eggshell (ES) waste as a composite filler has increased significantly in the last 5 years. This increase in usage took place due to its unique characteristics, which improve the properties of the resulting composite. Adding a weight fraction of ES particles into a composite can improve its mechanical properties, although not all studies have shown this phenomenon. Studies on these composites’ thermal and tribological properties are still limited, so more in-depth studies could be carried out. The degradation of composite performance due to friction or exposure to humidity and hot temperature is another area that is worthy of further study. In this work, we discuss changes in composites’ mechanical, thermal, and tribological properties associated with the addition of ES particles, examining both untreated particles and those treated with carbonation. This work can serve as a guide for the utilization of ES particles as an environmentally friendly composite material.

Friction brake material is important component in the braking system of the vehicles. These materials are usually made of asbestos and non-asbestos materials. Some non-asbestos materials use natural fibers as reinforcement and phenolic resin as a binder. The post-curing process is carried out by heating a material with specific temperature and time. During post curing, ammonia gas as the reaction of the phenolic resin and HMTA diffuses out from the friction brake material. The heating rate in post curing was supposed affecting process of removal ammonia gas from composite and it will affect mechanical properties of the composite. Therefore, this paper is concerned with effect of post curing method on the composite flexural strength. Composite specimen were manufactured by mixing the ingredients, preforming, hot molding and followed by post curing. Bending tests performed to determine the effect of post curing the flexural strength. The results showed that heating rate in post curing affected flexural strength of composite. Flexural strength of composite decreased with increasing heating rate. Internal defect that were formed during post curing decreased composite flexural strength.

Al 6061-Al2O3 composite is a lightweight materials that can be used as an alternative material in automotive parts. T6 heat treatment is generally used on aluminium alloy series 6xxx . On T6 heat treatment process, material heated to temperature for obtaining a single phase of α, quenched and then continued by artificial ageing. Quenching is critical step because distortion can be occur in material. The aim of this research is to investigated effect of quenching agent and electroless coating treatment of Al2O3 in distortion at Al 6061-Al2O3 composite . The distortion was measured by dimensional change in the specimen. Coordinate Measuring Machine (CMM) was used to measured distortion based on coordinate change. Lower distortion are occur on 10E and 10N specimens. Electroless coating process on the reinforcement is more effective to obtain lower distortion on Al 6061-Al2O3 composite. The severity (H) of quenchant influenced distortion on specimen. Higher H value produce higher distortion on Al 6061-Al2O3 composite.