Bolt Design Research Articles

Limit Design of Extended End-Plate Connections

A limit states method for the design of bolted end plate connections has been developed. The design method aims at providing connections whose strength and stiffness are adequate to sustain the ultimate moments of beams in rigid frames designed by plastic analysis. Basic design philosophy relating to strength and stiffness is considered. The force distribution within the joint is derived and design rules are formulated for the different elements of the connection. These include design of bolts, end plates and welds, together with checks on the adequacy of the column flange and web. Certain fabrication effects, such as lack of fit are considered. The paper combines the results of several research programs and reports experimental evidence from each. Mention is made of relevant research in the United States and Europe.

Criteria for Evaluating Bolt Head Design

The emphasis on reducing fastener weight, conserving material, and providing joint integrity has increased the importance of understanding the causes of bolt failure. In bolt design, a significant area where better material utilization can be achieved is the bolt head. This paper identifies the critical factors in head design which affect mechanical properties and presents a design procedure to determine the optimum head configuration.

Macrosound laboratory in Austria

The selection of the preload bolt is often an afterthought in the design of Langevin type “sandwich” transducers, but quite often it is the root cause of failure for power ultrasonic applications. The main role of the preload bolt is to provide a “prestress” in the piezo stack to prevent interface “gapping” or tension in glued joints which can result in delamination. But as an integral part of a highly tuned dynamic system, the resulting parasitic resonances in these preload bolts, such as bending or longitudinal modes, are often difficult to predict and control. This research investigates many aspects of preload bolt design for achieving optimal transducer performance, including basic size and strength determination based on drive amplitude, as well as ensuring adequate thread engagement to the mating horn. Other aspects such as rule-of-thumb configuration and length guidelines to reduce parasitic resonances are also investigated. Optimizing the uniformity of stress in the piezoceramics is also considered, which is affected by end mass length, counterbores and proximity to threading. The selection of the bolt material based on stiffness is also investigated as related to electromechanical coupling. The investigation focuses solely on Langevin type transducers used for semiconductor wire bonding, and which are comprised of the common Navy Types I and III (PZT4 and PZT8) piezoelectric materials. Several metrics are investigated such as impedance, displacement gain, and electromechanical coupling factor. The experimental and theoretical research methods include Bode plots, scanning laser vibrometry and finite element analysis.

Errata: Design of Bolts or Rivets Subject to Combined Shear and Tension

Errata

Discussion: Design of Bolts or Rivets Subject to Combined Shear and Tension

Discussion

Errata: Design of Bolts or Rivets Subject to Combined Shear and Tension

Errata

Design of Bolts or Rivets Subject to Combined Shear and Tension

The 1963 AISC specification introduced, in Section 1.6.3, new provisions pertaining to the combined tension and shear stresses in bolts and rivets. The formulas given in this section permit the checking of a given design but leave the design itself to a rather cumbersome cut and try procedure. The purpose of this paper is to present a simple method which enables the designer or detailer to establish the required number of bolts or rivets in a bracket connection—the most common case in which rivets or bolts are under combined action of shear and tension (see Fig. 1). The specification provides different criteria for various rivet types, high tensile bolts of the friction or bearing type and for unfinished bolts; for this reason a different analysis is required for each ofthese elements. This paper will deal, however, only with the most commonly used types, that is, ASTM A325 type high tensile bolts and A141 rivets.