Benjamin W. Schafer

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The tip asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. This enables robotic needle steering, which can be used in medical procedures to reach subsurface targets inaccessible by straight-line trajectories. However, accurate path planning and control of needle steering require models of(More)
— The asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. In this study we present a mechanics-based model that calculates the deflection of the needle embedded in an elastic medium. Microscopic observations for several needle-gel interactions were used to characterize the interactions at the bevel(More)
Keywords: Steel foam Elastic buckling Nominal strength Steel foam Local buckling Distortional buckling Thin-walled channel a b s t r a c t The objective of this paper is to explore the potential strength and serviceability implications of metallic foams, specifically steel foam, utilized as a thin-walled channel structural member. A typical advantage sought(More)
  • Benjamin W Schafer, Narutoshi Nakata, Stephen G Buonopane, Robert L Madsen, Devco Engineering
  • 2010
The objective of this brief paper is to introduce a newly funded research project: NEESR-CR: Enabling Performance-Based Seismic Design of Multi-Story Cold-Formed Steel Structures. The project focuses on lightweight steel framing using repetitive members. The project will provide (a) new modeling capabilities that incorporate cross-section limit states(More)
A series of cantilever tests on joist-sheathing assemblies were conducted to determine the rotational restraint that sheathing provides to the compression flange of a cold-formed steel floor joist in bending. This rotational restraint, characterized by the stiffness, k φ , can partially or fully retard distortional buckling. Tests were conducted for(More)
Local buckling, is an issue that hot-rolled steel design and construction generally tries to avoid through judicious selection of locally stable cross-sections. While slender cross-sections due see use in certain specific applications, in general, the additional complications in the design Specification procedures, limitations in analysis software (which(More)
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