Joints

7 tools in the Structures area.

Fastened Joint Stiffness

Calculates effective shear and tension fastener stiffness for a single or double lap joint.

Fastened Joint Strength

The following analysis calculates the ultimate and yield strength of a single-fastener shear joint. If input loads are given, a margin of safety for each is calculated.

This tool provides guidance when using non-structural shims in single-shear joints. Assumes all the fastener eccentric load is balanced by prying on the head and tail. Bearing distribution is assumed constant - metallic sheets/plates only.

Lug Strength

Strength of pin-loaded lugs by the method of Cozzone, Melcon and Hoblit (Product Engineering, May 1950 and June 1953) as codified in Section 9 of the Air Force Stress Analysis Manual, AFFDL-TR-69-42, with the allowables taken from MIL-HDBK-5J. Simple mode checks one lug in single or double shear with a rigid pin; Advanced mode analyses the whole joint lug by lug as in the manual's Table 9-1: double shear, single shear or a multiple-shear connection, with bushings and the pin. Axial, transverse and oblique loads, a side load for misalignment, lugs of low elongation, press-fit bushing stresses, the manual's lug design procedure and the fatigue life of 2024-T3 and 7075-T6 aluminum lugs. The results follow the manual's own order, every efficiency chart is reproduced at the step that reads it with the design point marked, and every equation is written out with its substituted numbers.

3 worked examples reproduced, listed on the tool page.

Bolt Group Loads

Load on each fastener of a bolted or riveted pattern under a general load set: in-plane forces and the moment about the pattern's normal are shared by the rigid-plate (centroid and polar) method, the direct shear in proportion to each fastener's weight and the torsional shear in proportion to its weight times its distance from the centroid; the normal force and the two in-plane moments give each fastener's tension by the same linear distribution. The weight is chosen from the industry conventions: equal fasteners, entered shear stiffnesses (elastic), shank area (equal fastener stress, Bruhn and Peery), bearing area D t (Niu), the fastener allowables (ultimate, each fastener at the same fraction of its strength) or the lesser of the fastener shear and sheet bearing allowables (Niu). The loads may act anywhere, since the tool transfers them to the centroid. Each fastener's shear and tension are checked against entered allowables with a shear-tension interaction, the critical fastener is reported with its margin at the chosen load level, and a figure draws the pattern with the centroid, the load point and the shear on every fastener.

Weld Group Stress

Stresses in a fillet-weld group treated as lines (Blodgett's method as presented in Shigley's Mechanical Engineering Design, Chapter 9): the throat area, centroid, unit second moments and the actual I and J of the group from one of the seven standard configurations of Shigley's Tables 9-1 and 9-2 or from entered weld segments with their own leg sizes; the loads at a point off the centroid transferred to it; the primary shear V/A, the secondary (torsional) shear M r/J and the out-of-plane bending stress M c/I at every weld end, added as vectors to find and locate the maximum; the weld-metal allowable by the AISC code allowable 0.30 F_EXX, by AISC 360 LRFD (φ 0.75 · 0.60 F_EXX, optional directional strength increase) or ASD (Ω 2.00), the distortion-energy yield check against the electrode yield strength, the base-metal shear check, the required leg size, the allowable force per unit length and margins of safety; an optional fatigue check by Shigley's method (Marin factors, the Table 9-5 fatigue stress-concentration factor and the Goodman line in shear). A figure draws the group with the centroid, the load point and the stress vectors at the critical point. The default case is Shigley's Example 9-1 (10th ed.): a 50 kN load carried by two plates into a 200 mm channel through 6 mm fillet welds in a channel pattern (b = 56 mm, d = 190 mm), 25 kN per plate at 100 mm from the channel edge, whose printed throat area, centroid, J, moment and primary and secondary shears the page reproduces.

1 worked example reproduced, listed on the tool page.

Beam-in-Socket

This beam-in-socket analysis produces maximum pin bearing stress, maximum pin shear and bending loads. Also referred to as a pin-in-socket analysis.

Other Structures sections

Materials · Composites · Frames and Trusses · Beams · Loads and Dynamics · Stress and Strain · Stability · Plates and Shells · Thin-Walled Structures · Contact · Stress Concentrations · Fatigue · Damage Tolerance