# Use of New and Light Materials in Automotive Engineering for Towing System
## 1 Introduction  
In the automotive industry, the share of steel in manufacturing has continuously decreased in the last 50 years, with countless components being replaced by other metallic, plastic, or composite materials. Plastics and composite materials have now, in some cases, made up half of a vehicle's weight. The most commonly used nowadays are composite materials. According to one study [1], the largest amounts of composite materials are used in the automotive and civil construction industries, using about 31% worldwide of the entire amount of composites manufactured for automotive engineering. Traditional metallic materials are increasingly being replaced by polymeric composite materials, with automobiles now containing up to 50% composite parts. In addition to the advantages of the low specific mass and high strength of composite materials, their tendencies to decrease life span and increase the number of vehicles impose good recycling capabilities on these materials; thus, revolutions in manufacturing technologies appear, developing modern production lines. Currently, plastic materials represent approximately 10% of the total mass of a motor vehicle, and this percentage is on an upward trend [2]. Composite materials present a whole series of advantages that recommend the replacement of classic materials. Their high ratio between strength and weight, dimensional stability over time, resistance to corrosion and against chemical agents, and good processingcapacity are just some of the exceptional characteristics of composites; they can successfully replace the most used metals in the industry--steel and aluminum. The disadvantages of composites are that they have a higher price than metals, are easily flammable, their resins emit toxic fumes, and they are harder to recycle than metals. New and composite materials are also based on new manufacturing processes, among which, additive manufacturing (AM) can currently be distinguished, which is based on a new philosophy of the incremental manufacturing of materials. Additive manufacturing involves layer-by-layer modeling and the consolidation of raw powder material into arbitrary configurations, normally using a computer-controlled laser [3]. Carbon nanotube composites are promising new materials with interesting applications in the automotive industry as well. The properties of these materials, as well as the scale of the dimensions they offer, lead to significant advantages in numerous applications, providing an increased strength, stiffness, impact resistance, and service life. All these advantages are summarized in [4], presenting basic results related to mechanical, electrical, and thermal properties. But nanocomposites have been proven to be a high-performance material. They also possess unusual combinations of properties and, as such, offer unique design possibilities. The growth rate of nanocomposite use is estimated at 25%. They are environmentally friendly and have proven to be extremely useful in the automotive industry [5]. Composites made of epoxy resins reinforced with natural fibers began to be used by car manufacturers in the production of door panels, seats, linings, dashboards, etc. Natural fibers offer advantages such as a low weight, low cost, and recyclability. Among these natural fibers are kenaf hemp, flax, jute, and sisal. However, in order to obtain quality materials, certain technical characteristics must be observed that must be obtained technologically [6]. The fuel savings and improved emissions being pursued in automotive engineering are driving the growing trend of replacing conventional steel and cast iron with composites or Al and Mg in vehicle manufacturing. However, there are technical issues that need to be resolved if this industry is to use lightweight materials. The main problem in need of a solution is the production of these materials at a reasonable price. A cost-benefit study is always necessary, and a study of these aspects is presented in [7; 8].