Predicting the behaviour of HSS double chord trusses—a comparison with test results

1983 ◽  
Vol 10 (2) ◽  
pp. 261-270 ◽  
Author(s):  
Robert M. Korol ◽  
Farooque A. Mirza ◽  
Ernie T.-C. Chiu

Predictions from a previously developed analytical model that takes into account plastic hinging action and includes the effects of axial load and moment interaction are compared with the results of tests on double chord RHS trusses. The model incorporates a shear spring mechanism that is applicable to gap joints of HSS trusses. Load–displacement curves generated by the program are in reasonable agreement with the majority of truss tests. However, calculated moment – axial force interaction curves tend more to predict trends of behaviour rather than to be quantitatively accurate.

2020 ◽  
pp. 60-68
Author(s):  
V. A. Pyalchenkov ◽  
D. V. Pyalchenkov

Research has found that the axial load applied to the bit is distributed unevenly along the crowns of the balls. The middle crowns are the busiest. The value of the axial force perceived by a separate ring is associated with the deformation of the details of the ball joint. You can reduce the uneven loading of crowns by shifting them along the ball along the radius of the bit, placing them so that the vertical line passing through the center of the lower ball of the lock bearing passes through the middle of the gap between the crowns of neighboring balls. The bits with the new option of placing the teeth on the balls were tested on the stand and in industrial conditions. For the bits of this design, the axial load was distributed more evenly over the crowns, which allowed increasing the efficiency of their work.


Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 150
Author(s):  
Yeon-Kyu Park ◽  
Geuk-Nam Kim ◽  
Sang-Young Park

The CANYVAL-C (CubeSat Astronomy by NASA and Yonsei using a virtual telescope alignment for coronagraph) is a space science demonstration mission that involves taking several images of the solar corona with two CubeSats—1U CubeSat (Timon) and 2U CubeSat (Pumbaa)—in formation flying. In this study, we developed and evaluated structural and thermal designs of the CubeSats Timon and Pumbaa through finite element analyses, considering the nonlinearity effects of the nylon wire of the deployable solar panels installed in Pumbaa. On-orbit thermal analyses were performed with an accurate analytical model for a visible camera on Timon and a micro propulsion system on Pumbaa, which has a narrow operating temperature range. Finally, the analytical models were correlated for enhancing the reliability of the numerical analysis. The test results indicated that the CubeSats are structurally safe with respect to the launch environment and can activate each component under the space thermal environment. The natural frequency of the nylon wire for the deployable solar panels was found to increase significantly as the wire was tightened strongly. The conditions of the thermal vacuum and cycling testing were implemented in the thermal analytical model, which reduced the differences between the analysis and testing.


2011 ◽  
Vol 255-260 ◽  
pp. 718-721
Author(s):  
Z.Y. Wang ◽  
Q.Y. Wang

Problems regarding the combined axial force and bending moment for the behaviour of semi-rigid steel joints under service loading have been recognized in recent studies. As an extended research on the cyclic behaviour of a bolted endplate joint, this study is performed relating to the contribution of column axial force on the cyclic behaviour of the joint. Using finite element analysis, the deteriorations of the joint performance have been evaluated. The preliminary parametric study of the joint is conducted with the consideration of flexibility of the column flange. The column axial force was observed to significantly influence the joint behaviour when the bending of the column flange dominates the failure modes. The reductions of moment resistance predicted by numerical analysis have been compared with codified suggestions. Comments have been made for further consideration of the influence of column axial load in seismic design of bolted endplate joints.


2014 ◽  
Vol 919-921 ◽  
pp. 1794-1800
Author(s):  
Xin Zhi Zheng ◽  
Xin Hua Zheng

Abstract: 7 square steel tubular columns were tested to discuss the ultimate axial bearing capacity, ductility performance and the steel consumption under stiffened by steel belts and binding bars of different cross-sections. Test results indicate that only by increasing fewer amounts of steel usage, stiffened square CFST columns with binding bars can not only improve the overall effects of restraint and alleviate regional local buckling between the binding bars, but also improve the bearing capacity of concrete filled square steel tubular columns. The utility benefits and the economical benefit is considerable, deserving extensive use.


Author(s):  
Ya. S. Hrydzhuk

The estimation approach of the work performed by the main force factors acting on the drill string, rotary and combined drilling methods, was proposed. The problem of obtaining analytical functions of force factors action for a mechanical system with distributed parameters was formulated. To solve the problem, the axial load and torque functions of the drill string analysis was performed, depending on the alternating parameter - the well depth. By integrating these functions, analytical dependencies were established for determining the axial load and torque acting on the drill string in sections of directional and S-shaped wells. Relying on industrial data, numerical calculations of the size of work on sections of such wells were carried out. The obtained research results can be further used to find energy-saving modes of the drill string.


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