Application of Pure Bending Moments to Crystals

1956 ◽  
Vol 27 (7) ◽  
pp. 546-547 ◽  
Author(s):  
John J. Gilman
Keyword(s):  
Bending Moments ◽  
Pure Bending

Pure Moment Testing for Spinal Biomechanics Applications: Fixed Versus 3D Floating Ring Cable-Driven Test Designs

2012 ◽  
Author(s):  
Jessica A. Tang ◽  
Justin K. Scheer ◽  
Christopher P. Ames ◽  
Jenni M. Buckley
Keyword(s):  
Spinal Column ◽  
Bending Moments ◽  
Pure Bending ◽  
Uniform Loading ◽  
Flexion Extension ◽  
Driven System ◽  
Accepted Standard ◽  
Pure Moment ◽  
Bending Modes ◽  
Biomechanical Tests

For spine biomechanical tests, the cable-driven system in particular has been widely used to apply pure bending moments. The advantages to pure moment testing lie in its consistency as an accepted standard protocol across previous literature and its ability to ensure uniform loading across all levels of the spinal column. Of the methods used for pure moment testing, cable-driven set-ups are popular due to their low requirements and simple design. Crawford et al [1] were the first to employ this method, but prior work by our group indicated a discrepancy between applied and intended moment for this system in flexion-extension only [2]. We hypothesize that this discrepancy can be observed in other bending modes and minimized with a second-generation floating ring design to eliminate off-axis loads.

Technical Basis for Application of Collapse Moments for Locally Thinned Pipes Subjected to Torsion and Bending Proposed for ASME Section XI

2014 ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Bostjan Bezensek ◽  
Phuong H. Hoang ◽  
Howard J. Rathbun
Keyword(s):  
Power Plants ◽  
Bending Moments ◽  
Finite Element Analyses ◽  
Pure Bending ◽  
Plastic Bending ◽  
Evaluation Procedures ◽  
Wall Thinning ◽  
Applicable Range ◽  
Technical Basis ◽  
Local Wall Thinning

Piping components in power plants may experience combined bending and torsion moments during operation. There is a lack of guidance for pipe evaluation for pipes with local wall thinning flaws under the combined bending and torsion moments. ASME B&PV Code Section XI Working Group is currently developing fully plastic bending pipe evaluation procedures for pressurized piping components containing local wall thinning subjected to combined torsion and bending moments. Using elastic fully plastic finite element analyses, plastic collapse bending moments under torsions were obtained for 4 (114.3) to 24 (609.6) inch (mm) diameter pipes with various local wall thinning flaw sizes. The objective of this paper is to introduce an equivalent moment, which combines torsion and bending moments by a vector summation, and to establish the applicable range of wall thinning lengths, angles and depths, where the equivalent moments are equal to pure bending moments.

Evaluation of Torsion and Bending Collapse Moments for Pipes With Local Wall Thinning

2011 ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Bostjan Bezensek ◽  
Phuong Hoang
Keyword(s):  
Power Plants ◽  
Bending Moment ◽  
Combined Loading ◽  
Bending Moments ◽  
Pure Bending ◽  
Evaluation Procedures ◽  
Wall Thinning ◽  
Loading Modes ◽  
Bending Fracture ◽  
Local Wall Thinning

ASME B&PV Code Section XI provides fully plastic bending fracture evaluation procedures for pressurized piping components containing flaws subjected to bending and membrane loads. The piping components in power plants may experience only bending moments but also occasionally small torsion moments, simultaneously. Currently, there is a lack of guidance in the Section XI for combined loading modes including torsion. Finite element analyses were conducted in this paper for 24-inch diameter straight pipes with local wall thinning. The pipe was subject to combined bending and torsion moments. It is shown that the effect of torsion moment on plastic collapse bending moment for the pipes depends on the local wall thinning sizes. In addition, it is found that the equivalent moments defined as the root of the sum of the squares (RSS) of the torsion and bending moments is equal to pure bending moments, when wall thinning depth is shallow.

Behavior of Damaged Tubular Structural Members

1985 ◽  
Vol 107 (3) ◽  
pp. 342-349 ◽  
Author(s):  
Y. Ueda ◽  
S. M. H. Rashed
Keyword(s):  
Experimental Study ◽  
Structural Unit ◽  
Nonlinear Behavior ◽  
Bending Moments ◽  
Structural Members ◽  
Biaxial Bending ◽  
Pure Bending ◽  
Space Frames ◽  
Theoretical Predictions ◽  
Interaction Relationship

An analytical model of dented tubular members is constructed. Using this model, an ultimate strength interaction relationship between axial force and biaxial bending moments is derived. The implementation of this interaction relationship to take account of denting and bending damage in the analysis of nonlinear behavior of tubular space frames by ISUM (the Idealized Structural Unit Method) is described. An experimental study of the behavior of dented members subjected to pure bending is reported. Comparison with theoretical predictions is presented.

On Finite Bending of Pressurized Tubes

1959 ◽  
Vol 26 (3) ◽  
pp. 386-392
Author(s):  
Eric Reissner
Keyword(s):  
Internal Pressure ◽  
Cross Sections ◽  
Linear Problem ◽  
Bending Moments ◽  
Pure Bending ◽  
Stability Parameters ◽  
Essential Step ◽  
Circular Rings ◽  
The Stability ◽  
Finite Bending

Abstract A unified treatment is presented of two well-known problems which have until now been considered separately. The two problems are: (a) the linear problem of pure bending of curved tubes, and (b) the nonlinear problem of pure bending of straight tubes. In both problems the effect of uniform internal pressure is included. The essential step in the present analysis is the treatment of the flattening of the cross sections of the tube by means of a theory of finite bending of circular rings. The general results of the paper are used to obtain improved values for the stability parameters in the problem of flattening instability of originally straight tubes acted upon by end bending moments, and also to obtain results on the effect of slight original curvature of the beam axis in the problem of flattening instability.

A Multi-Degree of Freedom System for Biomechanical Testing

1994 ◽  
Vol 116 (3) ◽  
pp. 371-373 ◽  
Author(s):  
David N. Kunz ◽  
Ronald P. McCabe ◽  
Thomas A. Zdeblick ◽  
Ray Vanderby
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Biomechanical Testing ◽  
Testing System ◽  
Closed Loop Control ◽  
Bending Moments ◽  
Pure Bending ◽  
Loop Control ◽  
Torsional Testing ◽  
Three Degrees Of Freedom

A system is described that allows axial, torsional, and bending testing of biomechanical specimens. The system uses electric motors under closed loop control in its grips allowing application of pure bending moments. These grips attach to an axial/torsional testing system. Thus, it provides simultaneous closed loop control of all three degrees of freedom (D.O.F), so that under any given test condition either the loads or the displacements for each D.O.F. can be maintained at zero, selected constant values, or simultaneously controlled. This enables the expedient evaluation of the mechanical behavior of biological structures under complex loadings or simple loadings (one D.O.F.) with no artificially induced constraints in the other two D.O.F.’s due to specimen mounting.

Technical Basis for Application of Collapse Moments for Locally Thinned Pipes Subjected to Torsion and Bending Proposed for ASME Section XI

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Bostjan Bezensek ◽  
Phuong H. Hoang ◽  
Howard J. Rathbun
Keyword(s):  
Power Plants ◽  
Plastic Collapse ◽  
Bending Moments ◽  
Pure Bending ◽  
Plastic Bending ◽  
Evaluation Procedures ◽  
Wall Thinning ◽  
Applicable Range ◽  
Technical Basis ◽  
Local Wall Thinning

Piping components in power plants may experience combined bending and torsion moments during operation. There is a lack of guidance for pipe evaluation for pipes with local wall-thinning flaws under the combined bending and torsion moments. ASME boiler and pressure vessel (B&PV) Code Section XI Working Group is currently developing fully plastic bending pipe evaluation procedures for pressurized piping components containing local wall thinning subjected to combined torsion and bending moments. Using elastic fully plastic finite element (FE) analyses, plastic collapse bending moments under torsions were obtained for 4 (114.3)–24 (609.6) in. (mm) diameter pipes with various local wall-thinning flaw sizes. The objective of this paper is to introduce an equivalent moment, which combines torsion and bending moments by a vector summation, and to establish the applicable range of wall-thinning lengths, angles, and depths, where the equivalent moments are equal to pure bending collapse moments.

Bending of Superelastic Wires, Part I: Experimental Aspects

1995 ◽  
Vol 62 (2) ◽  
pp. 459-465 ◽  
Author(s):  
B. T. Berg
Keyword(s):  
Phase Region ◽  
Constitutive Relationship ◽  
Tension Stress ◽  
Bending Moments ◽  
Pure Bending ◽  
Three Point Bending ◽  
Strain Relationship ◽  
Niti Wires ◽  
Mixed Phase Region ◽  
Constant Moment

A pure-bending apparatus is used to measure the constitutive relationship between applied pure bending moments and the resulting curvatures of a few superelastic alloy wires. The sample nickel-titanium alloy (NiTi) wires change phase when ample bending moments are imposed. Like the material’s uniaxial tension stress-strain relationship, the measured moment-curvature relationship shows plateaus of constant moment and hysteresis. The bent shape is circular, except in the mixed phase region where it is composed of a phase mixture of circles. An example of the applications of the measured moment-curvature relations is presented in Part II of this paper where the three-point bending problem is considered.

Sign in / Sign up

Export Citation Format

Share Document