ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

stresses were evaluated. The individual computational models were fixed on one side
and were loaded on the opposite side by means of pre-defined strain (0.1%).
5. RESULTS AND DISCUSSION
The local stress fields were analyzed in individual struts and local mechanical properties
were determined. 1 st and 3 rd principal stresses were evaluated on individual struts, see
Fig. 3. Maximum values of 1 st principal stress are located in most cases in the transient
region between strut and triple point. This can be caused by influence of struts geometry
change. Their stiffness is changed due to increases of thickness. Generally, the
maximum stress values are placed on the outside of struts. A comparison of 1 st and 3 rd
principal stress values is obvious that the 1 st principal stress plays important role in
behavior of struts.
Fig. 3. Samples of 1 st and 3 rd principal stresses on individual struts [MPa]
The dependence of 1 st principal stress on orientation of individual struts was analyzed in
the next part of this contribution. The orientation relating to loading axis was measured
as angle between the load plane (XY) and the axis of strut. The computed results are
shown in Fig. 4. Forty five struts were chosen randomly from computational model and
on these struts the 1 st principal stress and orientation were determined.
The graph can be divided into two main parts; from 0 to 40 degrees and from 40 to 90
degrees. The first set of results is typically for struts which are rather parallel to the load
plane. For the intended load (corresponding to elongation of the computational model
0.1%), the median of stress values was estimated as 87.2 MPa.
The second part of results is created by struts oriented rather perpendicularly to the load
plane. For such oriented struts the median of 1 st principal stress values were evaluated