The Bolt Bearing Response and Tensile Deformation Capacity of Plates Made from a Titanium Alloy Nicholas Tinl, C.C. Menzemer, A. Patnaik, and T.S. Srivatsan (Submitted July 28, 2011; in revised form November 11, 2011) In this article, the bearing capacity and elongation characteristics of bolt holes in a titanium alloy (i.e., Ti-6Al-4V) deformed in uniaxial tension is presented and discussed. The specific role played by bolt hole confinement on bearing capacity is highlighted. The nature of final fracture is examined and the intrinsic features present on the fracture surface are rationalized in concurrence with macroscopic mechanical response. The behavior of the candidate alloy (Ti-6Al-4V) is compared with conventionally preferred and chosen candidate materials steel and aluminum alloys. An empirical relationship suitable for purpose of structural design is proposed. Keywords bearing, deformation, failure, loading, plate, titanium alloy 1. Introduction Selection of the appropriate material does play a key and vital role in the process of structural design. It is important for a structural engineer to give due consideration to material properties, spanning strength, toughness, corrosion resistance, and density, when designing a structure for load-critical or stress-critical applications. During the design process, a failure to consider the purpose of the structure, the nature of loading on the structure, service requirements and expectations, and the environment to which the structure is expected to perform while in service, can result in inferior performance of the structure with either a withdrawal from ‘‘active’’ service or culminate in catastrophic failure. Traditionally, structural steel has been the candidate material for use in a spectrum of structural engineering applications that necessitate the need for a high specific strength (r/q). This in turn results in an efficient structural member that has the ability to sustain the necessary load while concurrently minimizing its dimensions. An additional advantage in selecting and using structural steel is due to its relatively low cost when compared one-on-one with other viable choices spanning the domain of metallic materials that can offer near similar properties. Of all the alloys of titanium that have been developed and put forth, it is the Ti-6Al-4V alloy that is the most preferred and attractive choice for use in both performance-critical and non-performance- critical structural applications. The Ti-6Al-4V alloy is to be noted for its innate ability to provide high strength at roughly half the density when compared to structural steels. In addition to its unique qualities spanning the specific domain of mechanical properties, the Ti-6Al-4Valloy also offers an excellent resistance to corrosion or environmental degradation (Ref 1). However, despite its many advantages, this and other emerging alloys of titanium have only seen limited selection for use in those applications involving an exposure to extreme conditions during actual service, such as, in the aerospace industry. This is largely because of the high production cost associated with the family of titanium alloys since they are categorized as a specialty material and concomitant production in limited quantities. Through the years, a gradual increase in the potential applications for the selection and use of the Ti-6Al-4V alloy as a structural material has provided the necessary impetus for increasing its production. This has been put in force in the titanium metal industry with a resultant reduction in cost of the specific alloy in various product forms. A key aspect that is both related and relevant to a materialsÕ intrinsic ability to perform under the influence of an external load or stress is its behavior or response in connections using mechanical fasteners. These connections find definite use in structures for the following reasons: (i) Ease and reliability of installation. (ii) An intrinsic ability to perform under dynamic loading. (iii) Cost is either comparable or marginally more than tradi- tional welding.Mechanical fasteners are required to per- form in a manner that necessitates the need to transmit large load over a relatively small area. As a direct conse- quence, they tend to develop concentrated stresses both within the bolt and the connected material making them susceptible to mechanisms that facilitate and/or enable their failure. The key mechanisms contributing to failure of an individual bolt, as opposed to failure of a group of bolts, can be any one or a combination of the following: (i) Failure of the bolt through shear. (ii) Shear tear-out of the connected material. (iii) Bearing failure of the connected material at the bolt-material interface. Nicholas Tinl, C.C. Menzemer, and A. Patnaik, Department of Civil Engineering, The University of Akron, Akron, OH 44325; and T.S. Srivatsan, Department of Mechanical Engineering, The University of Akron, Akron, OH 44325. Contact e-mail: tsrivatsan@ uakron.edu. JMEPEG (2012) 21:1696–1702 ÓASM International DOI: 10.1007/s11665-011-0100-4 1059-9495/$19.00 1696—Volume 21(8) August 2012 Journal of Materials Engineering and Performance