## 4 Results and Discussion
### Tests in Close-to-Real Conditions
#### 4.3.2 Long-Term Studies of Prototype Anchors
Daily temperature amplitudes generated a sinusoidal character of deformation changes contributing to intensification of anchor bending. Nevertheless, the most visible increases in the anchor bending arrow were seen in colder periods. For example, between the 10 th and 11 th measurement day, a greater bend growth of 0.18 mm was observed at a daily temperature amplitude of about 15 \({}^{\circ}\)C.  
The cumulative increase in the average daily temperature of the anchor over 100 days was 10 \({}^{\circ}\)C and led to a total displacement of 1.5 mm. Night-time cooling of the anchors mostly caused bursts of the top and bottom deformations. Such a cyclic amplitude resulted in gradual yielding of the material under the load. Depending on the deformation conditions, the magnitude of the changes of the internal energy and entropy may differ, since below the glass-transition temperature polymeric chains limited sterically by particles exhibit very little activity. The cause of this situation may be found in the production process of resin compositions where in the processing stage the component present in the mixture in a lesser quantity produces spherical domains in the matrix. Such a shape of the dispersed phase is energetically privileged as it offers a minimum internal energy in the system. Under deformation related to mould casting flow with narrow channels, such domains change shape into ellipsoids and produce stresses in the direction normal to the casting direction of the resin composition in the mould. Limited motion between the thin walls in the anchor project (Figure 19) might have also had an influence on the deformation of domains in the panel (just at the surface) and fibre direction within the X-type narrow channels. What is more, the dispersion process was inhibited by surface tension forces and the domains within the flow field might have undergone  
Figure 23: Example record of bottom anchor surface deformation changes taking into account temperature variation. sinusoidal deformations under the interface forces, creating, after cross-linking, a bimodal composite structure that was unnoticeable during the laboratory mechanical tests described in Section 4.1.1, Section 4.1.2, Section 4.1.3 If there were some changes caused by sedimentation forces within the cross section 2-2 during the several-hour-long cross-linking process (Figure 19), the homogenisation of the dispersed phase was disturbed. Thus, the share of the dispersed phase in the top anchor surface was lower than in the bottom surface, leading to a change in the composite morphological stability and its susceptibility to deformation under static bending forces in varying temperature conditions (Figures 22 and 23). The plots presented in Figures 22 and 23 show that the temperature change by 5 \({}^{\circ}\)C caused deformation of the top and bottom anchor surface by max 100 \(\mu\varepsilon\). In turn, the temperature change by 10 \({}^{\circ}\)C caused deformation of the top anchor surface by max 400 \(\mu\varepsilon\) and the bottom anchor surface by about 300 \(\mu\varepsilon\). The results may reflect not only the bimodal composite structure, but also the material tendency for spontaneous creeping at decreasing temperature. The character of the visible deformation changes over time depends mostly on the temperature, load acting time and most of all the viscoelastic properties of the main component. Moreover, it depends on the adhesion of the additive to this component and its dispersion degree, and thus the composite structure and anisotropy. A typical drawback in epoxy resin application is its crystallisation. What is most important, the crystallisation risk increases with a decreasing temperature and is a random phenomenon difficult to predict during the composite design stage:  
- Temperature > 12 \({}^{\circ}\)C: very low risk;  
- Temperature > 5-\(\sim\) 12 \({}^{\circ}\)C: high risk;  
- Temperature < 5 \({}^{\circ}\)C: very high risk.