Unconventional Tee Forming on Metal Tubes

An experimental machine using elastomer rod has been developed for the forming of tee-junction on metal tubes. This was achieved by applying loading-unloading cycles to the tube and the elastomer simultaneously. The success of the operation is governed by the so called “clearance height” which controls the relationship between the displaced volume of the elastomer and the reduced length of the tube. Present experiments have confirmed the validity of the empirical expression previously found. The upper-bound theory is found to be in good agreement with experimental results, for predicting the total forming load. The experiments were performed on materials with different work-hardening characteristics. In addition, the effects of other variables on the process are examined.

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Investigation of Bearing Strength of Single-Bolt Double-Lap Joints in Composite Laminate

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.577-578.573 ◽

2013 ◽

Vol 577-578 ◽

pp. 573-576

Author(s):

Li Nan Cheng ◽

Xi Tao Zheng ◽

Chun Yang Tan

Keyword(s):

Upper Bound ◽

Composite Laminate ◽

Lap Joints ◽

Test Results ◽

Engineering Approach ◽

Failure Region ◽

Static Zone ◽

Bound Theory ◽

Good Agreement ◽

Upper Bound Theory

Based on the Upper Bound Theory, a Simplified Engineering Approach is Presented to Determine the Ultimate Strength of a pin-Loaded Composite Laminate in this Papaer. According to the Upper Bound Theory, the Displacement Rate in a Given Ply is Divided into Two Zones: the Moving Zone and the Static Zone. the Applied Load Q that Associated with Displacement must be Less than the Maximum Resistance of the Laminate. in this Paper we have Discussed the Failure Region, Failure Type of each Ply and Simplified the Tsai-Wu Failure Criterion. Experiments of Single-Bolt Double-Lap Joints have been Conduncted According to ASTM D5961 Test Standard. Finally, we can Observe that the Engineering Approach is in Good Agreement with the Test Results.

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Infinite-Prandtl-number convection. Part 2. A singular limit of upper bound theory

Journal of Fluid Mechanics ◽

10.1017/s0022112006000450 ◽

2006 ◽

Vol 560 ◽

pp. 159 ◽

Cited By ~ 23

Author(s):

G. R. IERLEY ◽

R. R. KERSWELL ◽

S. C. PLASTING

Keyword(s):

Prandtl Number ◽

Upper Bound ◽

Singular Limit ◽

Bound Theory ◽

Upper Bound Theory

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Calculation of Punch Force and Maximum Pressure for Tube Extrusion

10.1115/imece2000-1880 ◽

2000 ◽

Author(s):

S.-H. Zhang ◽

Y.-L. Shang

Keyword(s):

Upper Bound ◽

Physical Modeling ◽

Steel Tube ◽

Experimental Results ◽

Maximum Pressure ◽

Punch Force ◽

Tube Extrusion ◽

Tooling System ◽

Very High ◽

Good Agreement

Abstract Punch force and maximum pressure for tube extrusion can be predicted with an upper bound theory-based program POLSK. Experiments of steel tube extrusion and wax physical modeling were performed. The punch force and the maximum pressure values were obtained. Comparisons were made among the experimental results, physical modeling results and upper bound predictions. It was found that a medium extrusion coefficient causes the lowest pressure on the tooling system, very low and very high extrusion coefficients can both cause very high pressure. It is proved that the upper bound predictions are in good agreement with the experimental results and the upper bound program is suitable for use of steel tube extrusion design.

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Calculation Method of Underground Cavern Loosening Pressure Based on Limit Analysis Using Upper-Bound Theory and Its Engineering Application

Mathematical Problems in Engineering ◽

10.1155/2020/5096931 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Zhiwei Wang ◽

Zhenghao Liu ◽

Weibin Ma ◽

Shaoshuai Shi ◽

Lin Bu

Keyword(s):

Upper Bound ◽

Limit Analysis ◽

Calculation Method ◽

Underground Cavern ◽

Disturbed Zone ◽

Underground Caverns ◽

Calculation Results ◽

The Difference ◽

Bound Theory ◽

Upper Bound Theory

From the point of view of the failure mechanism of the disturbed zone, this paper uses the limit analysis upper-bound theory to analyze the calculation formula of the loosening pressure, distinguish the difference between the vertical pressure and the horizontal pressure in the underground cavern, combine the loosening characteristics of the disturbed zone with the open-type disturbed zone and the annular disturbed zone, and construct the multirigidity slider translation and rotation failure mode to discuss the calculation method of surrounding rock loosening pressure of underground caverns in upper soft and hard rock stratum. The relevant calculation examples are given, and the application of the upper-bound theory of limit analysis is demonstrated in detail. Based on the actual engineering background, the calculation results of the calculation method of the loosening pressure of the cavity based on the upper-bound theory of the limit analysis are analyzed and compared for the different depths and different types of caverns. The difference, rationality, and applicability of the calculation results of this method are analyzed and discussed.

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Low-dimensional models from upper bound theory

Physica D Nonlinear Phenomena ◽

10.1016/j.physd.2010.06.010 ◽

2011 ◽

Vol 240 (2) ◽

pp. 241-248 ◽

Cited By ~ 5

Author(s):

Gregory P. Chini ◽

Navid Dianati ◽

Zhexuan Zhang ◽

Charles R. Doering

Keyword(s):

Upper Bound ◽

Dimensional Models ◽

Low Dimensional ◽

Bound Theory ◽

Upper Bound Theory

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A Field Method of Determining Gas Turbine Meter Performance

Journal of Basic Engineering ◽

10.1115/1.3425121 ◽

1970 ◽

Vol 92 (4) ◽

pp. 724-731 ◽

Cited By ~ 3

Author(s):

W. F. Z. Lee ◽

H. J. Evans

Keyword(s):

Gas Turbine ◽

Field Method ◽

Experimental Results ◽

Inexpensive Method ◽

Analytical Results ◽

The Relationship ◽

Good Agreement

The need for a simple and inexpensive method for field checking gas turbine meters exists. One such method called the “spin test” is described in this paper. The relationship between the change of “rotor coast time” of the spin test and the change of meter accuracy due to change of mechanical friction is formulated. Experimental results on two different 6-in. gas turbine meters are presented and show good agreement with analytical results.

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Study on the Critical Height of Homogeneous Clay Slope

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.3015 ◽

2011 ◽

Vol 368-373 ◽

pp. 3015-3021

Author(s):

Yue Nan Jiang

Keyword(s):

Upper Bound ◽

Sliding Mode ◽

Slip Surface ◽

Critical Height ◽

Energy Principle ◽

Bound Theory ◽

Upper Bound Theory

Small cohesion clay slope is possible to slide along the plane slip surface or log-spiral slip surface. Based on the upper bound theory and energy principle, this paper deduced the critical height of the inclined top clay slope. The sliding mode of plane slip surface and log-spiral slip surface is studied. Finally, an engineering example is analyzed and the critical height calculation is introduced.

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