Effect Of Static Axial Stress On The One-dimensional Elastic Rod Incident Wave

In recent years, for the frequent occurrence of earthquakes and demolition building(structure) building materials and actual types of underground rock and soil excavation project aims to achieve safe and efficient construction and disaster prevention, and stress waves in various types of rock and soil or propagation characteristics of concrete media has been one of the hot areas of research. When blasting stress wave propagation in underground rock, country rock at different distances from the earthquake has been static stress of varying sizes, which are mainly caused by the following two aspects: First, the original rock stress varies with the size of the space itself varies; Second, the underground engineering rock excavation unloading rock mass leads to the stress field in the vicinity of large changes. For this engineering background, this paper studies the impact of static axial stress incident stress wave, the first uniform axial static stress analysis of the incident and a half sine wave amplitude, angular frequency and phase of the early influence of waves; then analyzes the axial uniform static stress on stress wave distortion; finally simplified the initial stress load for a linear gradient, gradient influence of stress on the elastic rod stress amplitudes, wavelengths.The main contents and conclusions are as follows:(1) Through theoretical derivation studied elastic rod uniform axial static stress the magnitude of the incident half-sine amplitude, angular frequency, the initial phase of the relationship. When the punch at the same speed coaxial axially homogeneous static stress impact having an elastic rod, axially homogeneous static stress affect the magnitude of the incident angular frequency of the half sine wave, as axially homogeneous static stress is increased, the incident half gradually increasing the angular frequency of the sine wave; axial static stress even half the size of the impact of the incident in the early phase sinusoidal axial static load, the greater the absolute value of the initial phase of the sine wave incident, but the increment is small, take-off point for the lagging performance.(2) Negative( "tilt") conducted a brief analysis, research uniform static axial stress on the transmission wave length, the impact of the incident wave amplitude obtained for the experiment appear in the unloading station. Uniform axial static stress makes the incident appears unbalanced stress when unloading segment, making the incident particle reverse rod vibration, and thus a "tilt" phenomenon, and the greater axial compression, "tilt" the greater the value of its values axis half pressure; axial uniform static stress can also affect theamplitude of the transmitted wave, the greater axial compression, the smaller amplitude;uniform axial static stress also affects the wavelength of the transmitted wave, the greater the pressure shaft, The smaller wavelength.(3) Take the round rod in a homogeneous unit length stress analysis, derived using Newton’s second law with a gradient of stress in the general solution of the wave equation in the slender rod stress wave, the wave equation by solving the traveling wave method, and compared with no stress gradient through the solution of the wave equation, we get: an elongated round rod gradient stress stress amplitudes, the greater the stress gradient, the amplitude of the stress wave attenuation faster performance with the amplitude of the stress wave k increases and decreases; elastic modulus elongated round rod also affect the rate of decay of the stress wave amplitude, the stress gradient in the same circumstances, the larger the elastic modulus, the attenuation of the stress wave amplitude slower; an elongated round rod with a gradient of stress also affects the wavelength of the stress wave, the stress gradient,the smaller the wavelength of the stress wave, the performance of the wavelength of the stress wave decreases with the increase in k.