The effect of printing parameters (nozzle diameter, layer height, nozzle temperature, and printing speed), dimensions (wall thickness), and filament material on the crashworthiness performance of 3D-printed thin-walled multi-cell structures (TWMCS) undergoing quasi-static compression is presented. The ideal combination of parameters was determined by employing the Signal-to-Noise ratio (S/N), while Analysis of Variance (ANOVA) was utilized to identify the significant parameters and assess their impact on crashworthiness performance. The findings indicated that the ideal parameters for the specific energy absorption (SEA) consisted of a nozzle diameter of 0.6 mm, layer height of 0.3 mm, nozzle temperature of 220 °C, printing speed of 90 mm/s, wall thickness of 1.6 mm, and PLA(+) filament material. Afterward, the optimal parameters for crushing force efficiency (CFE) included a nozzle diameter of 0.8 mm, layer height of 0.3 mm, nozzle temperature of 230 °C, print speed of 90 mm/s, wall thickness of 1.6 mm, and PLA(ST) filament material. The optimum parameter to minimize manufacturing time is 0.3 mm for layer height and 90 mm/s for printing speed. This research presents novel opportunities for optimizing lightweight structures with enhanced energy absorption capacities. These advancements hold the potential to elevate passenger safety and fortify transportation systems. By elucidating the fundamental factors governing the crashworthiness of thin-walled multi-cell PLA 3D-printed tubes, this study contributes to a deeper understanding of the field.

The objective of this study is to detect flooded area in rice paddy fields in Indonesia by using remotely sensed data. We used synthetic aperture radar (SAR) data for this purpose, because it is capable of getting high-resolution data in almost all-weather conditions. The paper gives a result of detecting flooded area occurred in our research sites located close to Bandung area, Tegalluar in Bojongsoang district, from the end of February to the beginning of March in 2018. The C-band SAR data acquired by Sentinel-1 were used for this analysis. We derived the gamma-naught threshold for dividing flood and non-flood areas by using a linear discriminant analysis. Discriminant accuracy reached 98% using VV polarization. By using the gamma-naught threshold and rice paddy field mask (GIS data), the rice paddy flooded area could be extracted with good accuracy.

Challenge to use a light structural material for aero vehicle could be answered by fibre reinforced polymer composite. This composite has high ratio of strength to weight. In application this composite should be in mechanical assembling such as bolt. So that, investigation of hole introduction on the composite integrity and behaviours are needed. In this study, E-glass WR 185 fibres used as reinforcement in polyester BQIN EX 157 matrix. The composite made by hand lay-up methods; in which 13 layers of E-glass fibres were laminated one by one layer with polyester resin. After dried up, composite was cut off to made specimen for density, tensile and compression test. Some of tensile and compression specimens were drilled (marked as “open hole specimen”) in their centre. The result showed density of 1.12 g/cm3, maximum strength of 178 MPa (tensile) and 130 MPa (compressive). Introducing an open hole reduced strength to 119 MPa (tensile, decreased ∼33%), and to 112 MPa (compressive, ∼14%). Reducing strength is well confirmed with change of failure type; from lateral at grip top (LAT) to lateral gage middle (LGM). LGM of the open hole specimen means crack starting from the hole to both of lateral direction.

Loads at main landing gear while touchdown impact is function of aircraft weight and ground reaction load factor. In regulation states ground reaction load factor at V_sink = 3.05 m/s is below 3. Contact/impact force from simulation using MSC ADAMS is 94680 N, while using Solidworks Motion Analysis is 97691 N. The difference between MSC ADAMS and Solidworks Motion Analysis is 3.08%. The ground reaction load factor in MSC ADAMS is 2.78 while in Solidworks Motion Analysis is 2.87.

This paper investigates the crashworthiness characteristics of material applicated in LAPAN’s UAV (E-glass–Lycal & Al) under axial quasi-static crushing. The effects of ply numbers (5, 7, 9) of polimer matrix composites (PMCs) tube on crashworthiness have been studied. Subject to axial crushing the experimental tests exhibit that all of empty circular PMCs specimens undergo a progressive end collapse. E-glass–Lycal composite tube has specific energy absorption (SEA) increasing from 13.63 J/g to 23.74 J/g, and the local product aluminum tube has SEA of 32.93 J/g.