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This study aims to design and fabricate a prototype of massage chair made of corrugated cardboard materials and evaluate its structural strength. It could be a pioneering study as no one had manifested or discussed it before. The prototype is currently made with dimensions of approximately 60 ´ 50 ´ 100 cm, consisting of 6 cardboard components, affords a reflexology sensation from solid rubber balls, and provides reclinable features at the backrest and footrest. The most prominent benefit of this cardboard massage chair compared to the commercialized ones is environmentally friendly and lightweight products. Moreover, the constructed component can be disassembled and folded, making it a portable massage chair. From the strength evaluation, the cardboard massage chair can still endure a load of 50 kg to the prototype’s seat, backrest, and footrest. However, multi loading directions (e.g., vertical, longitudinal, lateral), stress concentration, and fluctuating person weight would generate tremendous stress and lead to a more substantial possibility of damage and failures on the cardboard after several testing cycles. Therefore, further improvement processes should be investigated to develop an optimized version of cardboard massage chair in the future.

This paper reveals the stability characteristics of an electric-powered delta trike (e-trike), which is developed for goods delivery services. The changeable center of gravity position and weight due to electric component placement and the carried good weight can cause instability of the e-trike. Three main parameters are firstly evaluated on the e-trike: 1) geometry, 2) center of gravity, and 3) stiffness and damping coefficient of the suspensions. Single Lane-Change (SLC) and Double Lane-Change (DLC) tests were then conducted following ISO 14791:2000 and ISO 3888-1:2018 standards, respectively. An e-trike model was created and simulated using SIMPACK, a multi-body dynamic software. The simulation results showed that the developed e-trike model can replicate SLC and DLC tests, indicating the model was valid. A parametric study with the validated model was then conducted with various e-trike weights, center of gravity position, and suspension stiffness and damping ratio values. The results showed additional weight and higher center of gravity position can decrease threshold velocity to avoid rollover. The low suspension stiffness also contributed to lower the threshold velocity. However, the damping coefficient value did not change the threshold velocity significantly. These results can be a guideline in designing a delta trike with better performance in stability and maneuverability.

This study derives a rollover index for a delta E-trike. Past works derive the rollover index by considering lateral centrifugal force only. In contrast, this study proposes a rollover index which is derived under the assumption that the centrifugal force act in both lateral and longitudinal direction. This assumption will give a result closer to the real-life application. In addition, a parametric study on the effect of center of gravity location on rollover index is also proposed. The study continued with the layout assessment, which is done as the considerations in rearranging the powertrain components inside the E-trike. The comparison between initial and new layout shows that the new arrangement gives several advantages to the delta E-trike.

This study aims to investigate the effect of rice husks’ particle size on resin-based brake pad performance (i.e. compressive strength, puncture strength, mass loss, wear rate, friction coefficient, and heat resistance). Bisphenol A-epichlorohydrin and cycloaliphatic amine were mixed to form resin and used as the brake pad's base material. In the experiment, rice husk with a specific particle size (i.e., 250, 500, dan 1000 μm) was added to the resin. Rice husk has received considerable interest due to its lignin, cellulose, and silica content, making it suitable as friction material due to its ceramic-like behavior. The experimental results showed small rice husk particles improved compressive strength, puncture strength, and bulk density. This can be obtained from the analysis of the maximum compressive strength for brake pad supported by particles with sizes of 250, 500, and 1000 μm having values of 0.238; 0.173; and 0.144 MPa, respectively. In contrast, large particles formed coarse surfaces and pores, decreased mass loss rate, and improve friction properties (i.e. wear rate, friction coefficient). The friction coefficient values of brake pad supported by particles with sizes of 250, 500, and 1000 µm were, respectively, 0.2075; 0.2070; and 0.3379. Particle size affected interpacking, interfacial bonding, pores number and size, thermal softening, mechanical properties, and friction properties of the brake pad. Comparison between the prepared resin-based and commercial brake pad was also done, confirming the utilization of agro-waste as a potential alternative for friction material in the brake pad.