Strength of materials

A. Nowadays the science Materials Strength is considered to be a basic engineering discipline. The initial study of this subject was undertaken* by the great Galileo.

The research into the problems of materials strength was markedly intensified in the 19th century. This research was of great importance for the industrial development of the society. Thousands of miles of railways were laid, bridges were erected at that time. People built tunnels and ocean-going ships, they used elaborate* apparatus and digged into the earth in searching for minerals.

B. A lot of structures built centuries ago have not only survived but remained in use. Some of them had been however destroyed because of the errors made by the builders. Sometimes tragedies happened, the buildings were destroyed, machines broke down or bridges collapsed. The reason for those failures was the lack of knowledge on the part of experts: the problems of materials strength were still hidden deep in the mysteries of atomic and molecular structures of materials. That is why it was necessary for any engineer to study the processes determining stresses and deformations in structures and machines under loading conditions.

C. The study on physics of materials strength was first undertaken in the 20th century. Mankind was already entering the age of high speeds, pressures and temperatures ,the age of advanced technology and new unknown materials.

In the 1920s the top speed of an airplane was not more than 200 kilometres per hour, the load per square metre of the wing area was about 50 kilograms. The main construction material was wood. Nowadays the speed of aircraft, even passenger planes, is approaching 3,000 km per hour, with the loads as high as 600 kilograms per square metre of wing. The turbine that drives such anaircraft is not only a miracle of a design, it is also a miracle of materials strength. The given examples are sufficient to illustrate the advantages of new costruction materials.

D. Creation of new materials is of tremendous importance for the further technological development of the society.

Chemists engaged in polymer research have developed synthetic rubbers*. Tyres* made of synthetic rubbers can cover distances several times exceeding the distance from the Earth to the Moon. Having tested a new class of aluminium alloys the metallurgists produced a new durable alloy. It turned to be of great use for aircraft and rocket engineering needs. The technological problem of substantial weight reduction of apparatus was solved due to the considerable material savings.

A further development of the science Materials Strengh will ultimately result in delicate bridges, light airy buildings, small but powerful machines and airplanes capable of carrying huge loads.

* to undertake the study of - начинать изучение

* elaborate - сложный; тщательно-разработанный

* alloy - сплав

* rubber - резина, каучук

* tyre - шина

Прочитайте текст и ответьте на вопрос:

1. Why does any engineer have to study Strength of

Materials?

A. ... to increase the engine efficiency

B. ... to analyse the stresses and deformations in the

structures and machines in order to prevent their failure

C. ... to estimate the cost of materials

D. ... to develop new materials

Завершите предложение в соответствии с основной темой абзаца:

2. The A passage is about ...

A. ...new discoveries in physics

B. ...advantages in the application of compound materials

C. ...the progress in the materials strength study in the 19th century

D. ...the development of modern electronics

Определите, в каком абзаце сообщается: