Semi-graphical method for plotting a frequency characteristic of impact noise level’s reducing

The article describes the application of rolled floor materials for sound insulation of impact noise by the floors. A detailed classification of such materials is given, including such materials as linoleum, rubber linoleum and carpet. The described method is appropriate for testing the floor to obtain the frequency characteristics of the normalized level of impact noise of the whole structure and for the frequency characteristics of improvement of sound insulation due to the use of roll coverings. Methods for normalized impact noise level indices calculation in case of composite construction and only roll covering are also briefly described. A new semi-graphical method for constructing the frequency response of reducing the level of impact noise by floor covering for inserted floors is presented. A computational model for solving the contact problem of the impact noise isolation by floor in the form of an oscillatory system, consisting of an absolutely solid body and a two-layer elastic medium, is presented. The solution of the contact problem for obtaining an adjustment for reducing the normalized level of impact noise due to the application of a roll material is shown. The equation for frequency of crumpling for the linoleum surface crumpling in the process of standard striking machine’s impact is shown. The effect of local crumpling occurs and the growth of sound insulation starts in two-layer floor from this frequency’s value. The analysis of calculations accordingly the proposed calculation method is carried out. The practical algorithm for semi-graphical method and for the frequency response plotting of impact noise sound insulation improving by the roll floor covering is proposed. Graphs of the magnitude of impact noise improvement by the most common roll materials, that can be used to obtain the frequency response of impact noise isolation by a two-layer floor, are given.