Improving the selection of bolted joint parameters by using results from finite-element analysis
Finite-element techniques were used to determine the combination of parameters that would produce the optimum design for the bolted joint. A finite-element model was constructed from a combination of two-dimensional isoparametric axisymmetric solid elements and gap elements. The gap elements represented the physical contact between the plate and bolt head and the plate and nut. The model was used to determine the stress patterns, displacements, and contact areas (separation diameters) across the bolted joint. Computed results for the contact area showed the following: the contact area is determined by joint design, not bolt Toad magnitude; joint thickness, plate thickness ratio, and bolt-head dimensions have a pronounced effect on the contact area; and the maximum contact area occurs with plates of equal thickness. The change in separation diameters (D) can be presented in a simple straight-line expression D/d = 1 + 1.1 (L/d), where L = joint thickness and d = bolt diameter. The stress results indicated that neither load nor stress distribution under the bolt head or nut is constant or uniform. Bolt-head dimensions, joint thickness, and plate thickness ratio markedly affect the developed stresses, with the maximum stress value occurring at the bolt-plate interface. Beyond the bolt head, maximum stress develops at the interface plane of the bolted plates, with that stress decreasing as the plate thickness ratio increases reaching its lowest value at the equal-thickness ratio. These results indicate that design stiffness formulas used heretofore are not adequate. Results provided by this analysis should prove more effective in achieving optimum bolt design for bolted joints.
- Research Organization:
- Westinghouse Hanford Co., Richland, WA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-87RL10930
- OSTI ID:
- 7138704
- Report Number(s):
- WHC-SA-1606; CONF-930361-1; ON: DE93002243
- Resource Relation:
- Conference: 1993 American Society of Mechanical Engineers (ASME) national design engineering conference, Chicago, IL (United States), 7-11 Mar 1993
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mechanical behavior of bolted joints under steady heat conduction
Evaluation of the method for lowering stress concentration at the thread root of bolted joints with modifications of nut shape
Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
BOLTED JOINTS
COMPUTER-AIDED DESIGN
DIMENSIONS
FINITE ELEMENT METHOD
OPTIMIZATION
STATIC LOADS
STRESS ANALYSIS
THICKNESS
CALCULATION METHODS
DESIGN
JOINTS
NUMERICAL SOLUTION
420200* - Engineering- Facilities
Equipment
& Techniques
990200 - Mathematics & Computers