Notes On SACS Ring Analysis - For Users
Notes On SACS Ring Analysis - For Users
Notes On SACS Ring Analysis - For Users
1. Introduction
Ring program is an interactive program where users define the ring geometry and loading
conditions, perform analysis and view results in a single interface.
2. Understanding the limitations of ring program,
a. Only English units supported currently, the loads can be input in kips for
concentrated force, inch-kips for moments and kips/inch for uniform force; the
angles are input in degrees and are positive clockwise.
b. The present version of the Ring program allows the analysis of Roark ring cases 1, 2,
3, 6, 8, 12, 16, 17 and 18. See Roark and Young, Formulas for Stress and Strain, 5th
edition, McGraw-Hill Book Company, 1975.
c. Three types of rings are currently supported: a rectangular section (no stiffener),
external and internal tee stiffeners.
3. Understanding the assumptions for the ring formulas
The following are assumptions applicable to the cases ring program supported from section
8.3, Roarks Formulas for Stress and Strain, 5th edition.
1) The ring is of uniform section;
2) It is such large radius in comparison with its radial thickness that the deflection theory for
straight beams is applicable;
3) It is nowhere stressed beyond elastic limit;
4) It is not so severely deformed as to lose its essentially circular shape;
5) Its deflection is due primarily to bending, but it is desired, the deflections due to
deformations caused by axial tension or compression the ring and/or by transverse shear
stresses in the ring may be included.
Or optionally user can browse into SACS system directory C:\Program Files\SACS53, find
the program SACWRNG.exe, and double click to launch the ring program interface.
5. Understanding the front end interface of ring programs
BE 1.1 DT
For rings without stiffeners, this should be the unit calculation width
corresponding to the input of loads. The program suggested value should
NOT be used in this case.
b. Stiffener:
i. When Stiffener option checked, user has options to define the stiffener as
External stiffener or Internal stiffener;
ii. Stiffener Web Height DS (units in inch);
iii. Stiffener Web Thickness TS (units in inch);
iv. Stiffener Flange Width BF (units in inch);
v. Stiffener Flange Thickness TF (units in inch).
c. Material Properties:
i. Program assumes the material properties are the same for both ring and its
stiffeners (if any);
ii. Yield Stress Fy (units in ksi), default to 36ksi;
iii. Youngs Modulus (units in 1000ksi), default to 29000ksi;
iv. Possions Ratio, default to 0.3;
d. Display the geometry
After the ring geometry input, click Apply, the ring and its stiffener (if any) will be
displayed graphically at the main window.
e. The geometry and material property input window looks like following,
After a basic load case is added, click View to view the added load case.
Repeat above procedures to add more basic load conditions. After a basic load case is added,
click View to view the added load case. An example basic load condition 2 with load type
2 and a load value of 2.0kips at a Theta angle T = 35.0 degrees looks like following,
A example load combination combines two basic load conditions are shown in following, the
load combination consists 100% basic load condition 1 and 75% basic load condition 2.
RING DEFINITION
Description of load combination cases used in this analysis is a summary of the basic
information of basic load conditions and load combinations. An example of output of this part
looks like following,
The third part is a deflection report part. The definitions in this part are based on the diagram
from Roark formulas,
The fourth part of the output results is the internal loads and stresses report. For each ring
analysis, the report will be based on 36 positions with each position 10 degrees apart to cover the
full 360 degrees. An example output of this part looks like following,
The analysis results will not be automatically saved. User must use the browser to save the
output listing file for future use or reference.
UserNotessonRingProggram12
UserNotesonRiingProgram13
UserNotesonRiingProgram14