Vibration is one of the problems of modern cities. Moreover, every year their intensity is constantly increasing. Why is modern science so actively exploring this problem? For what reason have vibration measurements become mandatory procedures in many organizations and enterprises? The fact is that vibration is a phenomenon that causes a number of occupational diseases, which gives doctors the reason to raise questions about measures to eliminate it.
Concept of vibration
Vibration is a complex oscillatory process that takes place over a wide frequency range. How does it arise? When transferring vibrational energy from a source to a solid body. Usually, vibration means mechanical vibrations that have a noticeable effect on the human body. This refers to the frequency range from 1.6 to 1000 Hz. Sound and noise are closely related to the concept of vibration. They accompany this phenomenon with high rates of vibrational motion.
What subject in school studies such a thing as vibration? This
BZD (life safety) is a very important subject. Ensuring labor protection is one of the main problems of Russia raised to the level of national security.
Sources of occurrence
Mechanical vibrations are phenomena that occur in almost all machines, machines and tools that have unbalanced or unbalanced rotating parts that make reciprocating and shock movements. The list of such equipment includes stamping and forging hammers, metalworking machines, pneumatic and electric perforators, as well as fans, compressors, pumping units and drives.
If oscillatory movements by mechanical bodies are performed with a frequency in the range up to 20 Hz, then they are perceived only as vibration. At high frequencies, sound appears. This is vibration with noise. At the same time, perception is produced not only by the human vestibular apparatus, but also by his hearing organs.
Vibration classification
Vibrational movements can be transmitted in various ways. So, there is a general vibration. This is an oscillatory process transmitted to the human body through various supporting surfaces. General vibration adversely affects the cardiovascular and nervous systems. In addition, it causes pathologies of the digestive tract and organs of movement.
In turn, the following are distinguished from the general vibration:
- transport that occurs when cars move on roads;
- transport and technical, the source of which is the machines and mechanisms involved in the process;
- technical, arising during the operation of stationary equipment or transferred to areas where service personnel are located, where there are no sources of vibration.
There is also local vibration. These are oscillatory movements transmitted through the hands. If a person encounters such vibration systematically, then he may develop neuritis with a simultaneous loss of working capacity.
When researching jobs, harmonic or sinusoidal vibration is distinguished. These are such oscillatory movements in which the values of their main indicator change according to a sinusoidal law. Such vibration is especially common in practice.
Oscillatory movements are distinguished by time characteristics. So there is constant vibration. Its parameters in their frequency during the observation period change no more than twice.
There is also a fickle vibration. It is characterized by a significant change in the main parameters (more than twice).
When studying a subject, are students given the opportunity to become more familiar with a phenomenon such as vibration? This is BZD. He is taught in high school.
Vibration Parameters
To characterize vibrational movements, the following values are used:
- the amplitude showing the greatest deviation from the equilibrium position in meters;
is the oscillation frequency, determined in Hz;
- the number of oscillatory movements within a second;
- oscillation speed;
- period of fluctuations;
- acceleration of vibrations.
Production vibration
Questions about reducing the level of vibrational movements that negatively affect the human body are especially relevant at the stage of developing a technological process that is impossible without the operation of machines, machines, etc. But, nevertheless, production vibration is a phenomenon that cannot be avoided in practice. It arises due to the presence of gaps, as well as surface contacts between individual mechanisms and parts. Vibration occurs when the equipment elements are unbalanced. Often, oscillatory movements increase many times due to resonance phenomena.
Carrying out vibration monitoring
To control and further reduce the level of vibration in production, special vibration measuring control and signaling equipment is used. It allows you to maintain the efficiency of obsolete equipment and increase the life of new machines and mechanisms.
Everyone knows that the technological process of any industrial enterprise requires the participation of a large number of fans, electrical machines, etc. In order for the equipment to not stand idle, technical services must carry out its timely maintenance or overhaul. This is possible when exercising control over the vibration level, which allows timely detection of:
- imbalance of the rotor;
- bearing wear;
- misalignment of gears and other malfunctions and deviations.
The vibration monitoring equipment installed on the equipment gives warning signals in case of an emergency increase in the amplitude of the oscillation.
The effects of vibration on human health
Oscillatory movements primarily cause pathologies of the nervous system, as well as tactile, visual and vestibular apparatuses. Professional drivers of motor vehicles and drivers complain of ailments of the lumbosacral spine. These pathologies are the result of the systematic effects of jerky and low-frequency vibration that occurs at their workplace.
Those to whom oscillatory movements of equipment are transmitted during the technological cycle suffer from pains in the limbs, lower back and in the stomach, as well as lack of appetite. They have insomnia, fatigue and irritability. In general, the picture of the effect of general vibration on a person is expressed in autonomic disorders, accompanied by peripheral disorders in the limbs, decreased sensitivity and vascular tone.
The impact of local oscillatory movements leads to spasms of the vessels of the forearms and hands. In this case, the limbs do not get the right amount of blood. Along with this, local vibration acts on bone and muscle tissues, as well as on nerve endings located in them. This leads to a decrease in the sensitivity of the skin, to the deposition of salts in the joints, to deformation and a decrease in the mobility of the fingers. It is worth saying that oscillatory movements in the low-frequency range sharply reduce the tone of the capillaries, and at high frequencies there is a vasospasm.
Sometimes a worker vibrates in the ear. What is this phenomenon? The fact is that the frequency of vibrational movements transmitted from operating equipment can be very different. However, in a single enterprise, there is a rather narrow range of such values. This leads to the appearance of one type or another of vibration, as well as the accompanying noise. So, sounds can have a low, medium and high frequency.
When does vibration occur in the ear? What characterizes this condition? The fact is that sometimes equipment creates oscillatory movements that are on the same level as auditory perception. As a result, there is noise transmitted to the inner ear through the body of the worker and his bones.
In practice, an acceptable level of vibration is distinguished. These are its values that do not adversely affect the human body. These parameters depend on many factors (on the time of exposure, the purpose of the room, etc.) and are measured by the amplitude of vibration, vibration velocity, vibration acceleration and frequency.
The most dangerous vibration levels
Features of the negative impact of vibrational movements on the human body are determined by the nature of their distribution with a combination of mass and elastic elements. In a standing person, this is the trunk, pelvis, and lower spine. When sitting on a stool, the upper body and spine are subject to negative influences.
The effect of vibration on human health is determined by its frequency spectrum. Those manual mechanisms, the oscillatory movements of which are lower than 35 Hz, contribute to the appearance of negative changes in the joints and the musculoskeletal system.
The most dangerous vibrations are close to the frequency of oscillation of human organs. This range is from 6 to 10 Hz. Fluctuations of this frequency also negatively affect psychological health. Such a frequency could well be the cause of the death of many travelers in the Bermuda Triangle. With oscillation values from 6 to 10 Hz, people have a sense of fear and danger. The sailors at the same time tend to leave their ship as soon as possible. Prolonged exposure to vibration can lead to the death of the crew. This phenomenon is dangerous for the functioning of both individual organs and the whole organism as a whole. It disrupts the central nervous system and metabolism.
Vibration with a large amplitude is very dangerous. It has a negative effect on bones and joints. With prolonged exposure and high intensity vibrations, such vibration provokes the development of vibrational disease. This professional pathology, under certain conditions, goes into cerebral form, which is almost impossible to cure.
Elimination of vibrational movements
How to avoid vibration in the body? What kind of activities should these be that will preserve human health? There are two main groups of similar methods. The activities of the first of them are designed to reduce vibration directly in the source of its appearance. Such actions carried out at the design stage, include the use of silent equipment and the correct selection of modes of its operation. During the construction and further operation of industrial buildings, these measures relate to measures for the use of technically sound equipment.
The second method to reduce vibration is to eliminate it along the path of propagation. For this, vibration isolation of equipment and air ducts is carried out, vibration-isolating platforms are being built, workplaces are equipped with special rugs and seats. In addition, vibration can be eliminated along the path of its propagation when performing a whole range of acoustic and architectural planning activities. Among them:
- location of vibration sources at the maximum distance from the protected objects;
- appropriate placement of equipment;
- application of the vibration-isolated and rigid fastening scheme of the unit, etc.
Time protection
In order to maintain the health of a person working with manual mechanisms or equipment transmitting oscillatory movements to the body, special modes of rest and work are developed. So, there is a limitation of the contact time with machines and mechanisms to 1/3 of a shift. In this case, two or three breaks of 20-30 minutes are necessarily arranged. Moreover, free time from work during the shift is provided for conducting industrial gymnastics and a variety of physiotherapeutic procedures.
Such modes of work are developed for vibro-hazardous professions and are a kind of preventive measures aimed at maintaining human health.
Numeric Name Vibration
In contact with different people, each of us behaves in completely different ways. And all this depends on the attitude to the interlocutor and on the current situation. We despise or respect, hate or love, listen to their opinion or it does not matter to us at all.
If the person encountered on the path of life is restrained and laconic, then such behavior becomes characteristic of us. The merry fellow and the joker, on the contrary, will make you laugh and will certainly cheer you up. How to find out that individuality of a person that is hidden in the depths of his soul? The vibration of the name will tell a lot. What is it? Numerological addition of consonants of the name. Using this method, you can determine the nature of relatives and spouse, friends and any person, not even knowing the date when he was born. Only knowledge of 9 numerical vibrations corresponding to the name is needed. With their help, you can pick up the key to the human soul and feel like a real magician. Not without reason, some say that this is the vibration of my heart. After all, using this method, a magical weapon appears in the hands of a person, which will benefit those who know its power of influence and basic significance.
The letters of the name of each person hide in themselves three meanings of his individuality. This is a numerical vibration:
- vowels;
- consonants;
- the sum of all letters.
These numerical values collectively characterize the most important aspects of the personality.
There is a sound vibration of the name, because life is a continuous movement. That is why it has its own vibration. Each name has its own vibration. Throughout life, its meaning is gradually transferred to the owner. Scientists believe that the lower threshold of such vibrations is at the level of 35,000 vibrations per second, and the upper one is at the level of 130,000 / sec. Those people who have the highest ratio are resistant to various kinds of infections. They also have high levels of moral attitudes.