The issue of earthquake and its destructive effects is constantly confronting human being communities as an extensive challenge. The ground, upon which we are constructing our buildings, is anything but solid. Hundreds of millions of years ago the continents were joined, but now they are dispersing ever so slowly. The idea that buildings are founded on stationary ground is only an illusion. From the viewpoint of geological time, the earth’s crust is in a continuous dynamic change. The scientific understanding of this process, known as continental drift or tectonic plate movement, which is the basic cause of most earthquakes, dates back only 100 years. Quakes strike at the heart of a community. When they damage buildings, people and animals are injured and killed. Earthquakes destroy the basic necessities of life, demolishing shelter, ruining food and water supplies and disrupting people’s livelihoods. Conversely, buildings that perform well during an earthquake, limit its impact on people and their basic needs. Scientists and building construction experts have strived in order to find the solutions for reducing structures damages which are caused by trembling of the earth and diminishing the casualty rate and also detriments, from some years ago. In our country, Iran, which is located in earthquake zone and has experienced some demolishing quakes before, this matter is more significant and remarkable. Apart from the poorest of communities for whom even partial earthquake protection is unaffordable, most of the disastrous effects of earthquakes are avoidable. Earthquake-resistant construction greatly reduces the rate of victims from a damaging quake, as well as lessening economic losses and disruption to public activities. Seismic retrofitting of existing buildings is of vital and crucial issues of our society. The purpose of rehabilitating is to reduce the vulnerability of a building’s inhabitants and the building itself, its structure, non-structural elements and possibly its contents to earthquake damage. To retrofit a building is to improve its seismic performance. One of the appropriate alternatives for enhancing the structural performance of available buildings is employing composites. These materials can be applied in order to increase the confinement, shear strength and ductility of columns and also enhance in-plane shear wall strength as well as out-of-plane resistance. In addition, with taking advantage of this kind of material, the secondary weight which would be added to the primarily structure is going to be significantly reduced and this would act as an optimum approach for rehabilitating the existing buildings.In this research, firstly the exact definition of composite materials and its components and different kinds are studied. Then, the essence of earthquake and seismic forces in addition to some topics on seismic retrofitting and the essential needs for it are discussed. Eventually, concerning the abilities of composites, employing them as a suitable technique for reconciliation of structural elements of existing buildings, which is one approach of seismic retrofitting, will be proposed with hope for presenting the essential knowledge of appropriate seismic retrofitting with efficient materials to architects and civil engineers in order to diminish the ruins of earthquake effects on structures and as a result, providing the next generations of our country with safer and much more protected circumstances.

Hybrid MMCs are a new class of materials that exhibit superior characteristics and functional response when compared to monolithic alloys and mono-reinforced MMCs, and thus have tremendous potential for widespread application in modern industrial and engineering applications. Since the manufacturing fraternity is proliferating, a cyclic evaluation of understanding the behavior of hybrid MMCs and their evolution is needed. Therefore, to address this necessity, this paper presents a detailed review of hybrid MMC manufacturing methods, materials (matrix and reinforcement) used, physicomechanical, tribological, and corrosion properties, and challenges associated with hybrid MMCs. This retrospective investigation presents the state of the art of hybrid MMC materials in the categories involving matrix materials and their alloys, ceramics reinforcements and secondary reinforcements, and the applications and formation of microstructures. This paper also discussed the overview and the status of various matrix and reinforcement materials in manufacturing hybrid MMCs using different fabrication methods. Further, the significant challenges associated with the fabrication of hybrid MMCs using different manufacturing methods, such as distribution of reinforcement, wettability, and other common limitations identified in the literature, are presented. This paper provides a broad-spectrum attitude on hybrid MMCs techniques, challenges, and future research directions.

Carbon nanotubes (CNTs)-reinforced Al composites have attracted attention due to their high specific strength and low density, which makes them suitable for the use in aerospace and automobile industries. In this review, preparation methods of Al/CNTs composites for achieving a homogeneous desperation of the CNT in the Al matrix are summarized. In addition, the effect of processing methods on carbon nanotube distribution and enhancement of mechanical properties such as toughness, wear behavior and hardness of the nanocomposites are reviewed. Improvement of mechanical characteristics was observed by the incorporation of carbon nanotubes into aluminum matrix. The strengthening factors gained by the carbon nanotubes addition are the interface of metal and CNTs and the chemical and structural stability of CNTs.

This paper presents a Novel method for fabricating of thin ceramic plates. Although achieving nearly full density, the commercial hot pressing machine have extremely high price and upkeep cost. The device presented in this paper have lower cost and for hot pressing, needs just an ordinary electrical furnace.Despite all this benefits, it can just form thin ceramic plates. In this paper, initially a brief description about ceramic matrix composites (CMCs) is presented and the effect of formed components and forming methods on its properties is discussed. Then the powder forming methods with advantages and disadvantages is presented. In the next step the device (expansional hot pressing device) and its working method is introduced. And finally this device is used for forming of a special ceramic matrix composite and the mechanical and microscopic properties of the formed part is examined and the method proves to be useful for forming CMCs.