JEC COMPOSITES MAGAZINE - Issue #51 - September 2009 - 53

Soluzioninventive s.r.l. approached the product with a completely new concept, creating a patented modular structure consisting of three parts that can be folded as shown in Figure 4. Dina-Lynt S8000 (63% glass fibre) was used to apply the concept. The resulting weight of 625 g is within the range of existing conventional hollowFig. 4: Foldable ice axe design profile metal ice axes, e.g. in patented by Soluzioninventive s.r.l. aluminium. However, an aluminium ice axe using a comparable three-part foldable concept would have weighed about 1 kg, too heavy to be used for mountain rescue or mountain sports. The ice axe was moulded in self-coloured SMC, eliminating the need for a painted finish and, therefore, any wear and tear on the colour due to mechanical impact or low temperatures. For safety reasons, yellow was chosen. Only composite technology could be used for such a low-weight modular concept. In contrast to conventional hollow-profile metal axes, the new concept and the reduced length when folded allow carrying the composite ice axe on the belt of the backpack, making it easily and safely accessible for unfolding and for rapid use. It also offers greater safety in case of fall, reducing the risk of injury from the pick. Also the fact that the SMC shaft is not electrically conductive contributes to the safety of the part. In a load situation, the biggest deformations are observed at the points connecting the three parts. A static load led to deformations of up to 2 mm (see Figure 6) that did not impair the functionality and safety of the ice axe. Dynamic loading tests were also necessary for approval by the International Mountaineering and Climbing Federation (UIAA). One of the tests is illustrated in Figure 7. In the drawing, the little arrows mark the points were the part was fixed. The bigger arrow shows where the static load was applied by increments Fig. 2: Flexural strength (red line) and residual strength of Dina-Lynt S8000 after cyclic load with 10%, 20%, and 30% of flexural strength in a three-point bending arrangement. Increasing the load to 70% of the load at break leads to tremendous differences between Dina-Lynt S8000 and conventional-matrix SMC. As Table 2 shows, the number of cycles until break is higher by more than a factor of 5 with Dina-Lynt S8000, compared to the conventional-matrix SMC. Fig. 3: Comparison of the dynamic load resistance of standard-matrix SMC (45% glass fibre) and Dina-Lynt S8000 (58% glass fibre). Due to these properties, the material is suitable for a variety of applications where, amongst others, the classical strength properties of metals are demanded. Ice axes are an application that needs these properties in a particular way. They require strength and impact strength including at low temperatures, high elongation at break, and elasticity. Dina-Lynt S8000 possesses such properties, along with a lower density than metals. It also offers great design freedom, despite its high glass content. In close collaboration with Polynt S.p.A., the designer Fig. 5: Modular concept for foldable ice axe produced with Dina-Lynt S8000 structural SMC. No51 September 2009 / jec composites magazine 53

JEC COMPOSITES MAGAZINE - Issue #51 - September 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #51 - September 2009