Vibrations are one of the problems of modern megacities. And every year their intensity is constantly increasing. Why is modern science so actively exploring this problem? What is the reason why vibration measurements have become mandatory procedures in many organizations and enterprises? The fact is that vibrations are a phenomenon that causes a number of occupational diseases, which gives reason to doctors to raise questions about measures to eliminate it.
The concept of vibrations
Vibration is a complex oscillatory process, which is carried out in 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 tangible 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 at high rates of oscillatory motion.
What subject at school studies such a thing as vibration? This is BZD (life safety) - a very important subject. Ensuring labor protection is one of the main problems in Russia,elevated to 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 reciprocate and shock. The list of such equipment includes stamping and forging hammers, metalworking machines, pneumatic and electric hammers, 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 a vibration. At high frequencies, sound appears. It's vibration with noise. At the same time, perception is produced not only by the vestibular apparatus of a person, but also by his hearing organs.
Vibration classification
The oscillating movements can be transmitted in various ways. So, there is a general vibration. This is an oscillatory process that is 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, which occurs when cars move on roads;
- transport and technical, the source of which are machines and mechanisms involved in the technological process; - technical, arising during the operation of a stationaryequipment or transmitted to service personnel areas where there are no sources of vibration.
There is also a local vibration. These are oscillatory movements transmitted through the hands. If a person systematically encounters such a vibration, then he may develop neuritis with simultaneous disability.
Harmonic, or sinusoidal vibration is highlighted in workplace studies. These are oscillatory movements in which the values of their main indicator change according to a sinusoidal law. This vibration is especially common in practice.
Oscillatory movements are also distinguished by the time characteristic. So, there is a constant vibration. Its frequency parameters change no more than twice during the observation period.
There is also a fickle vibration. It is characterized by a significant change in the main parameters (more than twice).
When studying what subject, students are given the opportunity to become more familiar with such a phenomenon as vibration? This is BJD. It is taught in high school.
Vibration parameters
To characterize oscillatory movements, the following quantities are used:
- amplitude showing the largest deviation from the equilibrium position in meters;
- oscillation frequency, determined in Hz;
- number oscillatory movements within a second;
- oscillation speed;
- oscillation period;- oscillation acceleration.
Industrialvibration
Questions about reducing the level of oscillatory movements that negatively affect the human body are especially relevant at the stage of developing a technological process, which is impossible without the operation of machine tools, machines, etc. But, nevertheless, industrial vibration is a phenomenon that practically impossible to avoid. It arises due to the presence of gaps, as well as surface contacts between individual mechanisms and parts. Vibration also occurs when the equipment elements are unbalanced. Often, oscillatory movements increase many times due to resonance phenomena.
Vibration monitoring
To control and further reduce the level of vibration in production, special vibration-measuring control and signal equipment is used. It allows you to maintain the performance of outdated 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 not to stand idle, technical services must carry out its timely maintenance or overhaul. This is possible when monitoring the level of vibration, which allows you to timely detect:
- rotor imbalance;
- bearing wear;- gear misalignment and other malfunctions and deviations.
Vibration monitoring equipment installed on the equipment issues warning signals in case of an emergency increase in amplitudefluctuations.
Effect of vibration on human he alth
Oscillatory movements primarily cause pathologies of the nervous system, as well as tactile, visual and vestibular apparatus. Professional drivers of vehicles and machinists complain of ailments of the lumbosacral spine. These pathologies are the result of the systematic impact of shock and low-frequency vibration that occurs at their workplace.
Those who are exposed to the oscillatory movements of the equipment during the technological cycle suffer from pain in the limbs, lower back and stomach, as well as lack of appetite. They develop insomnia, fatigue and irritability. In general, the picture of the impact of general vibration on a person is expressed in vegetative disorders, accompanied by peripheral disorders in the limbs, a decrease in sensitivity and vascular tone.
The impact of local oscillatory movements leads to spasms of the vessels of the forearm and hand. In this case, the limbs do not receive the required amount of blood. At the same time, local vibration affects the bone and muscle tissues, as well as the nerve endings located in them. This leads to a decrease in the sensitivity of the skin, to the deposition of s alts in the joints, to deformity and reduced mobility of the fingers. It is also worth mentioning that oscillatory movements performed in the low-frequency range sharply reduce the tone of capillaries, and at high frequencies, vasospasm occurs.
Sometimesworker vibration occurs in the ear. What is this phenomenon? The fact is that the frequency of oscillatory movements transmitted from operating equipment is very different. However, in a single enterprise, there is a rather narrow range of such values. This leads to the appearance of one or another type of vibration, as well as the accompanying noise. So, sounds can have low, medium and high frequencies.
When does vibration occur in the ear? What does this state characterize? The fact is that sometimes the equipment creates oscillatory movements that are on par with auditory perception. As a result, noise is transmitted to the inner ear through the body of the worker and his bones.
In practice, the permissible level of vibration is distinguished. These are its values that do not have a negative impact on the human body. These parameters depend on many factors (on the exposure time, purpose of the room, etc.) and are measured by the vibration amplitude, vibration velocity, vibration acceleration and frequency.
Most dangerous vibration levels
Features of the negative impact of oscillatory movements on the human body are determined by the nature of their distribution with a combination of mass and elastic elements. For a standing person, these are the torso, pelvis, and lower spine. When sitting on a chair, the upper body and spine are affected.
The impact of vibration on human he alth is determined by its frequency spectrum. Those manual mechanisms, oscillatory movementswhich are below 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 vibrations of human organs. This is the range from 6 to 10 Hz. Fluctuations of this frequency also negatively affect psychological he alth. This frequency could well be the cause of the deaths of many travelers in the Bermuda Triangle. With fluctuation values from 6 to 10 Hz, people have a feeling of fear and danger. At the same time, sailors 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.
Very dangerous vibration with a large amplitude. It has a negative effect on bones and joints. With prolonged exposure and high intensity of vibrations, such vibration provokes the development of a vibration disease. This occupational pathology, under certain conditions, turns into a cerebral form, which is almost impossible to cure.
Elimination of oscillatory movements
How to avoid vibration in the body? What kind of measures should be taken to preserve human he alth? There are two main groups of such methods. The activities of the first of them are designed to reduce vibration directly at the source of its occurrence. Such actions, carried out at the design stage, provide for the use of silent equipment and the correct selection of its operating modes. During construction and lateroperation of industrial buildings, these activities relate to measures for the use of technically sound equipment.
The second method to reduce vibration is to eliminate it in the path of propagation. For this, vibration isolation of equipment and air ducts is carried out, vibration isolating platforms are built, workplaces are equipped with special rugs and seats. In addition, it is possible to eliminate vibration along the path of its propagation by performing a whole range of acoustic and architectural planning measures. Among them:
- location of vibration sources at the maximum distance from protected objects;
- appropriate placement of equipment; - application of a vibration-isolated and rigid mounting scheme for the unit, etc.
Time protection
In order to preserve the he alth of a person working with manual mechanisms or equipment that transmits oscillatory movements to the body, special modes of rest and work are being developed. So, there is a limit on the time of contact with machines and mechanisms up to 1/3 of the shift. At the same time, two or three breaks of 20-30 minutes are necessarily arranged. Moreover, free time from work during the shift is provided for industrial gymnastics and various physiotherapy procedures.
Such modes of work are developed for vibration hazardous professions and are a kind of preventive measures aimed at maintaining human he alth.
Numeric name vibration
In contact with different people, each of us behaves in completely different ways. And it all dependsfrom the attitude to the interlocutor and from the current situation. We despise or respect, hate or love, listen to their opinion or we don't care at all.
If a person met on the path of life is restrained and laconic, then such behavior becomes typical for us. The merry fellow and joker, on the contrary, will make you laugh and will certainly cheer you up. How can one find out the individuality of a person that is hidden in the depths of his soul? The vibration of the name will tell you a lot. What is it? Numerological addition of consonants of a name. With this method, you can determine the nature of relatives and spouse, friends and any person, without even knowing the date when he was born. It is only necessary to know the 9 numerical vibrations corresponding to the name. With their help, you can pick up the key to the human soul and feel like a real magician. No wonder some say that this is the vibration of my heart. After all, with the help of this method, a magical weapon appears in the hands of a person, which will benefit those who know its power of influence and its main meaning.
The letters of the name of each person hide three meanings of his individuality. This is a numerical vibration:
- vowels;
- consonants;- the sum of all letters.
These numerical values together characterize the most important aspects of a person.
There is also 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 significancegradually 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 coefficient are resistant to various kinds of infections. They also have high levels of moral attitudes.
