A panel sandwich consists of two GRP or FRP sheets (face sheet and core) that are fused together. The core is a flexible material such as EPS, XPS or polyisocyanurate foam, or a solid such as styrofoam or a honeycomb. These sandwich panels are used in a variety of applications and are becoming more and more popular. They are lightweight, durable and cost-effective. They also have good thermal insulation properties and can provide a wide range of design options for any project, from simple walls and roofs to high-rise buildings and bridges.

In addition to providing structural integrity, they are often designed to offer acoustic insulation and sound barriers. This is especially important in urban environments where noise pollution is a major concern. Previously, heavier permanent structures were used to control sound transmission; however, lightweight sandwich panels can still provide the same protection without the need for excessive mass.

The most fatigue sensitive points in sandwich panels are the bonded interfaces between skin plates and the core material. This is because of the repeated concentrated loads that occur during a normal loading cycle. These stresses can cause damage to the skin-core bond or even the core itself.

Sandwich panels are therefore designed with a Hierros en Monforte high degree of fatigue resistance in order to minimize the occurrence of failure in these areas. The selection of the skin and core materials is a key factor in this regard. Moreover, the coatings on the face sheets are designed to be resistant to corrosion and wear caused by weather conditions such as rain, snow, humidity and altitude. The use of a plated alloy coating on the core ensures that the core is not exposed to corrosion at high temperatures.

Another key consideration is the blast resistance of sandwich panels. Various studies have investigated the effect of core thickness and front-face-sheet damage on the blast performance of sandwich panels. For example, Study A involved comparing the response of 30 and 40 mm thick P800 foam cores to 30 kg C4 charges at 14 m stand-off distances. The results indicated that the higher-density foam produced better performance than the lower-density material.

The blast-resistant qualities of sandwich panels can also be improved by the use of a polyurethane layer. Applied to the back face of the panel, it reduces both front-face deflection and particle velocity, thus improving the blast response of the structure. Another way to enhance the blast-resistance of sandwich panels is by using auxetic cores. Auxetic cores consist of a mixture of different material types, including granular mineral wool and a polyisocyanurate foam. These cores are able to combine a low flammability with very good insulating properties, as well as excellent stiffness. This combination makes them a suitable alternative to traditional mineral wool and styrofoam cores. They are also lighter and more cost-effective than solid styrofoam. Additionally, they have a more uniform geometry than conventional cellular concrete. Consequently, they have the potential to be a significant advance in blast-resistant construction.