Andi Kuswoyo, M.T.
Lecturer
Research Interest:
Mr. Kuswoyo’s research interests include experimental and computational composite materials and structures.
Education
- Bachelor Degree, (2015). Aerospace Engineering, Institut Teknologi Bandung, Indonesia. Project: “Preliminary design of strength analysis software for laminate composite structure”.
- Master Degree, (2017). Aerospace Engineering, Institut Teknologi Bandung, Indonesia. Thesis: “Buckling optimization of composite stiffened panel: blade stiffener”.
Latest Publications
Composite material is being used in vehicles for protective structures against blast loading. Limited data is available which compare experimental works and numerical analysis in the open field environment. More data is needed in this area in order to be able to predict and use composite materials safely. Methods: In this work, the response of woven glass/epoxy composite plates under blast loading was investigated, both experimentally and numerically. The plate was manufactured using glass/epoxy woven Cytec 120 °C curing system. The explosive material was Tri-Nitro-Toluen (TNT) with different masses, which are 60, 80, and 100 g. The stand-off distance was also varied, ranging from 300 up to 1000 mm. In the experimental work, a sewing needle pin was put under the plate to record the maximum deformation of the plate during TNT explosion. In the numerical analysis, LS-DYNA was used extensively. The composite plate was modeled as shell elements using MAT54, and the failure criteria was Chang-Chang failure criteria. The explosive TNT material was modeled in two different ways. First, it was modeled using CONWEP and the second was modeled using Smooth Particle Hydrodynamics (SPH). The numerical analysis results were then compared with the experimental data for the case of maximum deformation. Results: Experimentally, the sewing needle method was able to measure the plate maximum deformation during the explosion. The numerical analysis showed that the SPH model gave better agreement with experimental results compared with CONWEP method. The SPH results were in the range of 8–18% compared to experimental data, while the CONWEP results were in the range of 14–43%. Conclusion: Albeit its simplicity, sewing needle method was able to measure the maximum deformation for blast loading experimentation. The SPH model was better compared with CONWEP method in analyzing the response of composite plate subjected to blast loading.
The paper discusses the failure of cylindrical natural bamboo of the types Gigantochloa pseudoarundinacea and Gigantochloa apus
under compressive loading. Both numerical analysis and experimentation were discussed. There were three types of bamboo structures to be analyzed: without bamboo node, center node and end node. The length of the bamboo structure was 500 mm. Finite element analysis was performed in order to find the buckling strength of the structures. It was found that Gigantochloa pseudoarundinacea was able to withstand the first buckling load up to 80,000 N while the Gigantochloa apus was able to carry up to 40,000 N compressive loadings. Experimentation was done in order to compare with the numerical analysis. It was found that the bamboo structures were able to carry post-buckling loads beyond the first buckling strengths. The failure modes were also investigated.
Composite material is gammg acceptance for protective structures agamst exploston, such as granade explosion.
This is due to its lightness and high strength. In this paper, the response of composite plate subjected to granade explosion was studied experimentally. The composite plate was made of glass and carbon fiber with different number of plies and lay-up. The plate dimension wa 250×250 mm. The granade contains 40 grams of TNT and the shell was made of cast iron. The total mass of the granade was 365 grams. The stand-of-distance was veried, which was 300, 500 and 1000 mm. The results showed that all specimens were able to keep their integrity without collapse. The carbon fiber composites showed some small fragmet penetration, while the glass fiber composites showed no fragment penetration although some delaminations occured. The almunium plate showed fragment penetration and large plastic deformation. Therefore in this case, composite plates performed better than the aluminium plates.
Flatwise tension strength of sandwich structure is important for designing a sandwich construction since it provides failure mechanism and
debonding strength between the skin faces and the core, as well as (i) core strength and (ii) face strength of the sandwich structures.
The flatwise tension strength is affected by many factores: method of core preparation, test environment, testing speed, etc. In this paper, the ambient test temperature was 23 deg C and the humidity was 65%. The testing speed was 0.5 mm/min. Four different core preparations were investigated. ASTM C297 was used as a standard method to get the strength values. Two processes were employed to cure the adhesive during core-to-face bonding. It was found out that cleaning the core with Methyl-ethyl-ketone (MEK) and drying further in an oven gives maximum flatwise tension strength of the sandwich structures, with the value of 5.9 MPa. The data base is important for both the manufacturing and design engineers. For the manufacturing engineers, the data provides a value for process qualification, while for design engineers it gives a maximum allowable strength for designing sandwich construction for tensile loads.
In this paper, natural fiber composites made of treated ramie yarn and high-density polyethylene (HDPE) matrix in powder form were manufactured using hot compression molding. The fibers were arranged to make unidirectional ([0°] and [90°]) and bidirectional [0°/90°]s specimens. A Charpy impact test with a notch was performed to determine the impact strength of ramie/HDPE composites. Statistical analysis using two-parameter Weibull distribution with 50% reliability was used. The result showed that the unidirectional [0°] specimen has a higher impact strength than the bidirectional specimen. Meanwhile, the unidirectional [90°] specimen had the lowest impact strength. The morphology of the fracture surface was analyzed using scanning electron microscope (SEM). It revealed the dominant damage mode, i.e., fiber breakage and pull-out for the unidirectional [0°] specimen, matrix cracking for the unidirectional [90°] specimen, and the combination of matrix cracking and fiber pull-out for the bidirectional specimen.