Engineering Materials - Coursework Example

In addition, glass is very similar to a slowly moving liquid so that old pieces of glass seem thicker at the bottom than at the top. In order to increase the tensile strength of the glass, the molecules must keep very strong hold with one another. Surface finishing and ion-exchange are two chemical processes that are applied to strengthen glass materials (Chemically strengthened glass, 2011). Q3. The Giffith’s theory reflects the relationship between crack length at fracture and applied nominal stress.

It is a comprehensive equation that can be effectively employed for engineering purposes. Giffith’s theory says that steel is a safer engineering material than glass. It is experimentally proved that the stress required to fracture a glass is nearly 100 MPa. It indicates that comparatively a smaller stress is enough to fracture a glass and therefore, this material is not advisable for engineering purposes. In contrast, since a higher stress is required to fracture a steel material, it can strengthen buildings and other engineering constructions (Simple Stress).

In short, steel is a very stronger material as compared to glass substances. Civil engineers would suggest stronger and durable components for their projects since they are built for a long time.Q4. A metal or any other structural material will undergo a change in its shape when a sufficient load is applied to it and this change in shape is called deformation. Elastic deformation is a process by which a temporary shape change. takes place and the material comes to its original shape when the applied force is removed.

Plastic deformation will be uniform between the elastic limit and ultimate tensile strength (UTS). It means uniform plastic deformation is applicable only between certain limits and it will be non-uniform once the UTS is exceeded. It is assumed that the interface between a larger hole and a smaller hole has a direct impact on local plastic deformation. The interconnection between the “array angle of larger holes and the development of the shear band” can greatly influence local plastic deformation (SAO/ NASA ADS physics abstract service). Q5. “Rubber elasticity involves flexible molecular chains which need to be interconnected to prevent gliding.

” (Francois, Pineau, and Zaoui, 1998, p.67). Rubber elasticity necessitates a high temperature in order to ensure the adequate mobility of the molecular chains. Rubber elasticity’s entropic nature can be attributed to the large number of possible configurations for the molecular chains. As discussed earlier, rubber elasticity requires high temperature and it promotes mobility of molecular chains. This feature is one the main causes for rubber elasticity to low swiftness and high tension. Q6.

The combination of thermosetting resin and glass fibers produces composite materials which are tough even though both the primary elements are brittle. It is necessary to note that transfer of stress between reinforcing fibers and acting as a glue to hold the fibers together are