Kunigal N. Shivakumar¹, Anil Bhargava², Sameer Hamoush³

CMC-Computers, Materials & Continua, Vol.6, No.2, pp. 71-92, 2007, DOI:10.3970/cmc.2007.006.071

Abstract A detailed and accurate three-dimensional finite element stress analysis was conducted on countersunk rivet holes in a plate subjected to tension loading. The analysis included a wide range of countersunk depths, plate thicknesses, countersunk angles and plate widths. The study confirmed some of the previous results, addressed their differences, provided many new results, and investigated countersunk angle and width effects. Using the detailed FE results and the limiting conditions, a general equation for stress concentration was developed and verified. More >

D.Taylor¹

Structural Durability & Health Monitoring, Vol.2, No.1, pp. 1-10, 2006, DOI:10.3970/sdhm.2006.002.001

Abstract Current theories of fracture recognize the importance of material length scales, i.e. parameters having the dimensions of length which are included, either explicitly or implicitly, in many methods of fracture prediction. This paper is a review of the development of one particular approach, which we have called the Theory of Critical Distances (TCD). The history of this approach -- which is presented here for the first time - is a story of parallel developments in the areas of fatigue and brittle fracture and in different material fields: metals, polymers, ceramics and composites. A particular milestone More >

Kunigal N. Shivakumar¹, Anil Bhargava¹, Sameer Hamoush²

CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 97-106, 2006, DOI:10.3970/cmc.2006.003.097

Abstract A detailed three-dimensional finite element stress analysis was conducted on straight-shank and countersunk rivet holes in a plate subjected to tension loading. The study included a wide range of plate width to radius, thickness to radius, countersunk depth to thickness ratios and countersunk angles(θ_c). The stress concentration is maximum at or near the countersunk edge. The stress concentration depends on countersunk depth, plate thickness and width and it is nearly independent of the countersunk angle for 80° ≤ θ_c ≤ 120°. Using the finite element results and limiting conditions, an equation for stress concentration factor is More >

Kunigal Shivakumar¹, Anil Bhargava²

CMC-Computers, Materials & Continua, Vol.1, No.2, pp. 173-190, 2004, DOI:10.3970/cmc.2004.001.173

Abstract The fiber optic sensor (FOS) embedded perpendicular to reinforcing fibers causes an `Eye' shaped defect. The length is about 16 times fiber optic radius (R_Fos) and height is about 2R_Fos. The eye contains fiber optics in the center surrounded by an elongated resin pocket. Embedding FOS causes geometric distortion of the reinforcing fiber over a height equal to 6 to 8 R_Fos. This defect causes severe stress concentration at the root of the resin pocket, the interface (in the composite) between the optical fiber and the composite, and at 90° to load direction in the composite. The… More >