Traditional Large Power Transformer (LPT) tanks have been typically designed with a rectangular g... more Traditional Large Power Transformer (LPT) tanks have been typically designed with a rectangular geometry. The variation in LPT tank geometry to accommodate a completely different geometry for LPTs has not been considered much in research and literature. This preliminary work presents an initial analysis of two LPT tank geometries: the common one, and the proposed one using pressure vessel theory and finite element analysis methods. Further, apart from the effect of geometry on the mechanical reliability of LPT tanks, this study investigates the effect of a change in the tank's material from traditional low-carbon steel (LCS) to Polymer Matrix Composites (PMCs). The result shows that a capsular type of tank geometry made with Carbon Fiber Reinforced Polymer (CFRP) material potentially offers superior resistance to internal pressure loading 10 times higher than the tank with a rectangular geometry made with LCS material. The design limit for an LPT's internal pressure is about 0.2 MPa, and this capsular design is shown to accommodate 10 times this pressure limit. The outcome of this study, therefore, proposes a new geometry for further investigation for application in LPT tanks.
This paper posits a potential improvement in the impact strength of a published sandwich structur... more This paper posits a potential improvement in the impact strength of a published sandwich structure using the scientific facts from empirically proven techniques in literature. The previously published sandwich structure consists of five plies of unidirectional Carbon Fiber Reinforced Polymers (CFRP) as facesheets and a ten ply unidirectional Glass Fiber Reinforced Polymer (GFRP) as the core. The structure was used in a low-velocity impact experiment. The improvement to the structure's impact resistance for a high-velocity ballistic application is discussed. The PU material in this case is used as a 'converter', which converts a high-velocity projectile to a near low-velocity one at the onset of the impact. By using polyurea (PU) elastomer additions to the facesheets, and a functionally graded plain weave architecture that is graded along the through-thickness as a substitute for the unidirectional laminated core, the impact resistance of the structure can be greatly increased. Using graded woven composite core can improve the through-thickness stiffness of the sandwich. The improved stiffness of the functionally graded woven layered composite core was confirmed with an opensource TexGen4SC software by using a sigmoid function for generating the graded crimp values.
This paper posits a potential improvement in the impact strength of a published sandwich structur... more This paper posits a potential improvement in the impact strength of a published sandwich structure using the scientific facts from empirically proven techniques in literature. The previously published sandwich structure consists of five plies of unidirectional Carbon Fiber Reinforced Polymers (CFRP) as facesheets and a ten ply unidirectional Glass Fiber Reinforced Polymer (GFRP) as the core. The structure was used in a low-velocity impact experiment. The improvement to the structure’s impact resistance for a high-velocity ballistic application is discussed. The PU material in this case is used as a ‘converter’, which converts a high-velocity projectile to a near low-velocity one at the onset of the impact. By using polyurea (PU) elastomer additions to the facesheets, and a functionally graded plain weave architecture that is graded along the through-thickness as a substitute for the unidirectional laminated core, the impact resistance of the structure can be greatly increased. Using graded woven composite core can improve the through-thickness stiffness of the sandwich. The improved stiffness of the functionally graded woven layered composite core was confirmed with an opensource TexGen4SC software by using a sigmoid function for generating the graded crimp values.
Traditional Large Power Transformer (LPT) tanks have been typically designed with a rectangular g... more Traditional Large Power Transformer (LPT) tanks have been typically designed with a rectangular geometry. The variation in LPT tank geometry to accommodate a completely different geometry for LPTs has not been considered much in research and literature. This preliminary work presents an initial analysis of two LPT tank geometries: the common one, and the proposed one using pressure vessel theory and finite element analysis methods. Further, apart from the effect of geometry on the mechanical reliability of LPT tanks, this study investigates the effect of a change in the tank's material from traditional low-carbon steel (LCS) to Polymer Matrix Composites (PMCs). The result shows that a capsular type of tank geometry made with Carbon Fiber Reinforced Polymer (CFRP) material potentially offers superior resistance to internal pressure loading 10 times higher than the tank with a rectangular geometry made with LCS material. The design limit for an LPT's internal pressure is about 0.2 MPa, and this capsular design is shown to accommodate 10 times this pressure limit. The outcome of this study, therefore, proposes a new geometry for further investigation for application in LPT tanks.
This paper posits a potential improvement in the impact strength of a published sandwich structur... more This paper posits a potential improvement in the impact strength of a published sandwich structure using the scientific facts from empirically proven techniques in literature. The previously published sandwich structure consists of five plies of unidirectional Carbon Fiber Reinforced Polymers (CFRP) as facesheets and a ten ply unidirectional Glass Fiber Reinforced Polymer (GFRP) as the core. The structure was used in a low-velocity impact experiment. The improvement to the structure's impact resistance for a high-velocity ballistic application is discussed. The PU material in this case is used as a 'converter', which converts a high-velocity projectile to a near low-velocity one at the onset of the impact. By using polyurea (PU) elastomer additions to the facesheets, and a functionally graded plain weave architecture that is graded along the through-thickness as a substitute for the unidirectional laminated core, the impact resistance of the structure can be greatly increased. Using graded woven composite core can improve the through-thickness stiffness of the sandwich. The improved stiffness of the functionally graded woven layered composite core was confirmed with an opensource TexGen4SC software by using a sigmoid function for generating the graded crimp values.
This paper posits a potential improvement in the impact strength of a published sandwich structur... more This paper posits a potential improvement in the impact strength of a published sandwich structure using the scientific facts from empirically proven techniques in literature. The previously published sandwich structure consists of five plies of unidirectional Carbon Fiber Reinforced Polymers (CFRP) as facesheets and a ten ply unidirectional Glass Fiber Reinforced Polymer (GFRP) as the core. The structure was used in a low-velocity impact experiment. The improvement to the structure’s impact resistance for a high-velocity ballistic application is discussed. The PU material in this case is used as a ‘converter’, which converts a high-velocity projectile to a near low-velocity one at the onset of the impact. By using polyurea (PU) elastomer additions to the facesheets, and a functionally graded plain weave architecture that is graded along the through-thickness as a substitute for the unidirectional laminated core, the impact resistance of the structure can be greatly increased. Using graded woven composite core can improve the through-thickness stiffness of the sandwich. The improved stiffness of the functionally graded woven layered composite core was confirmed with an opensource TexGen4SC software by using a sigmoid function for generating the graded crimp values.
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Papers by Dr. Jide Williams