Mechanics in XXI century

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Кафедра ТМ > Интересные ссылки > Механика в XXI веке

Здесь приводятся наиболее яркие достижения в области механики за годы, прошедшие с начала третьего тысячелетия.

Achievements on planet Earth[edit]

  • On August 1st, 2012 the Russky Bridge was opened in Vladivostok. The main bay of the bridge reaches 1104 meters in length which makes the bridge to be the longest among cable-stayed bridges in the world. Before the bridge was built Sutong Yangtze River Bridge (China) was the longest. Construction of the bridges from early ages defined technology level of countries where the bridges were built. It required deep knowledge of mechanics in order to construct them. It is easy to recall several catastrophes due to incorrect analysis of the bridge structures. The examples are The Tay Bridge disaster in 1879 (UK) Tacoma Narrows Bridge disaster in 1940 (USA). In both cases the catastrophe occurred due to incorrect dynamic analysis of the bridge subjected to wind loading.
  • On January 4th, 2010 The Burj Khalifa was opened in Dubai, UAE. Its height equals 828 meters which makes it the tallest structure in the world. Before the skyscraper was built the tallest structure was Warsaw radio mast which collapsed in 1991. The significant height of the structure required solving a number of complex mechanical problems among which were the structure’s stability analysis, resistance to the wind loading, construction of high altitude elevators and water supply systems.
  • On January 5th, 2005 a group of American astronauts discovered Eris which is a dwarf planet situated farther than the orbit of Pluto. Eris’ weight and size exceed the weight and size of Pluto. This discovery together with the discoveries of a number of smaller objects of the size compared to Pluto’s size that took place in 2000-2005 lead to rethinking of what a planet is and how the Solar System is organized. As a result, Pluto lost its status of a planet and together with the similar objects was classified as a dwarf planet. The number of planets in Solar System have decreased to 8. It is worth noting that the way the planets orbit the sun is entirely a mechanical problem, which solution actually helped to discover the 8th planet, Neptune.
  • On October 22th, 2014 an article (Novoselov et al. 2004) was published by British and Russian scientists in the Science journal. It reported a purely mechanical synthesis of graphene, a two-dimensional material comprising of a single layer of the carbon atoms. In 2010 the two authors, Geim A.K. and Novoselov K.S. were awarded the Nobel Prize in Physics for "groundbreaking experiments with two-dimensional material graphene." The existence of two-dimensional materials was previously considered impossible. Graphene has unique mechanical properties, its rigidity and strength superior to all the known materials. In addition, being essentially a two-dimensional material, it allows one to take a fresh look at the theory of plates and shells, which was previously treated primarily as an approximate theory to describe three-dimensional objects.
  • On December 3th, 2001 American inventor Dean Kamen introduced The Segway, a compact electric driven vehicle allowing a person to ride it in a standing position. The device has two wheels on the each side of the driver, the vertical position stabilization of a human is performed by a system that regulates the rotation speed of the wheels. Segway is similar to Kapitza's pendulum, a pendulum that is stabilized in the vertical position by vibration. It was investigated by Academician Kapitsa P.L. in his pioneering work (Kapitsa, 1951). Segway takes a little more space on the road than an ordinary pedestrian, but it can move at a speed up to 20 km/h over rough terrain, the battery provides a mileage of about 40 km. Over the past decade Segway has gained popularity in the tourism sector, Segways are used by the police in some countries. The further spreading of Segways is hindered by their relative high cost, however, it is clear that the development of technology will solve this problem.

Achievements in space[edit]

  • On August 6th, 2012 The Mars rover Curiosity (USA) is safely delivered to the surface of Mars, that has served as the beginning of a new research mission on Mars. Curiosity can call full-fledged laboratory on wheels (weight of 900 kg), the robot of the similar size and complexity never studied other planets before. The equipment that was produced in Russia is installed on its board too.
  • On October 9th, 2009 As a result of an impact experiment the LCROSS has found water ice in the polar region of the Moon. The presence of water on the Moon surface makes possible its future colonization.
  • On May 25th, 2008 The Phoenix spacecraft (USA) has landed in the polar region of Mars. The conducted researches have allowed to find the water ice under a layer of soil. Availability of water testifies a possibility of existence of the living organisms on Mars in the past, and, perhaps, at the present.
  • On January 14th, 2005 spacecraft Huygens has made landing on the surface of Titan, the largest satellite of Saturn. It was found that rivers and lakes of liquid methane based out of a heavy atmospheric layer at the surface of Titan. The discovery gave background for new hypothesis about the possibility of methane-based and hydrogen-based life on Titan, instead of traditional hypothesis about oxygen-based and water-based life.
  • On January 4th and 25th, 2004 Mars rovers, Spiritand and Opportunity (USA) were delivered to the opposite side of Mars. Rovers researched planet`s surface and the atmospheric composition, while moving across the red planet and transferring data and high-quality photos to the Earth. Results of the research, for instance, gave evidence of water presence in the past.

Unachievement of the 21st century[edit]

thumb|right|Последняя посадка [ Шаттла] ([ Атлантис], июль 2011 г. )|200px

  • On 8 July 2011 was the 135th and final blastoff if the program «Space Shuttle». Currently, Russia is the only country that performs manned missions to the Global Space Station. The shuttle flight program was severely undermined after Space Shuttle Columbia Disaster on February 1, 2003, when Columbia disintegrated as it re-intered Earth atmosphere. The cause of the disaster was piece of foam insulation broke off from the Space Shuttle external tank and struck the left wing of the orbiter.
  • On 26 November 2003 was the «Concord», final flight than ended the era of supersonic commercial aviation. The disaster, which have led to death of the «Concord» on July 25, 2000, with the departure from Paris airport «Charles de Gaulle» was key factor for the termination of «Concordia» operation. The accident occurred as a result of hitting the landing gear wheel on a metal fragment happened on the takeoff runway, resulting in damage to the skin, wastage of fuel and fire outbreak.
  • On September 11, 2001 World Trade Center was destroyed (WTS) was destroyed by an unprecedented terrorist attack in New York. . The highest skyscrapers of New York, World Trade Center twin towers crashed at full speed controlled by terrorists civilian airliner Boeing 767. Towers outstand the impact of airliner, but fire arose in them led to the collapse of towers less than two hours after the collision. The reason for the destruction was that the supporting steel columns began to bend under high temperature stress and redistribute the load, because of what has been exceeded the strength of the material column. As a result, it started a collapse of the upper floors, gave rise to a chain effect – the towers developed on the basis of a house of cards. Only 5 years later the construction of new buildings in the WTC area.

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