Abstract: A non-destructive and non-invasive method and apparatus determines the structural integrity of discrete pieces of material, such as bone, medical implants and structural parts by determining the impact ratio of a striking mass that impacts and rebounds from the material. The impact ratio is equal to the ratio of instantaneous velocity of the striking mass immediately after the impact to the instantaneous velocity of the striking mass immediately prior to impact. A means can be used to force the striking mass towards the material to impact the material. In this case, the measured history of the displacement during the impact and the rebound are used to compute the impact ratio, the ratio being directly related to the impact reaction of the material. The impact ratio can be used to determine the structural integrity of the material or the onset of osteoporosis.

Abstract: The density of a discrete piece of hard tissue such as a bone in a patient may be determined by either of two methods. In a first method, an impulse of energy is introduced into the tissue, and the resulting vibration in the hard tissue is sensed and analyzed to compute the modal damping factor of the tissue, the modal damping factor being directly related to the density of the tissue. In a second method, a continuous energy input is introduced into the hard tissue. The resulting vibration in the tissue is measured with a mechano-electrical vibration transducer and a modal damping factor is calculated. The electro-mechanical vibration transducer of the preferred embodiment measures the pressure with which the transducer is pressed against the patient's flesh and only produces the continuous energy input when a predetermined pressure is achieved which is sufficient to prevent any significant vibration of the flesh surrounding the bone.

Abstract: The integrity of structures may be determined by either one of two methods. In a first method, an impulse of energy is introduced into the structure, such as by striking the structure, and the induced vibration is measured and the modal damping factor is calculated, the modal damping factor being directly related to the integrity of the structure. In a second method, a continuous energy input is provided to the structure for inducing a continuous vibration in the structure. This continuous vibration is measured with a transducer and a modal damping factor is calculated with a computer. The computer uses an algorithm to estimate the modal damping factor of the structure by calculating a theoretical response of an idealized system from several assumed parameters and varying those parameters until the difference between the measured response of the structure and a theoretical response of the idealized system is within an acceptable margin of error.

Abstract: The fatigue integrity of metallic materials may be determined by either one of two methods. In a first method, an impulse of energy is introduced into the material, such as by striking the material (20), and the induced vibration is sensed and analyzed in order to compute the damping factor thereof, the damping factor being directly related to the fatigue thereof. With this method, a transducer (28) is coupled to the material and its output is amplified by an amplifier (30) before input to a computer (32) which determines the damping factor. In a second method, a continuous energy input is provided to the material, such as by utilizing a frequency generator coupled to a power amplifier whose output drives a transducer such as a speaker or the like for inducing a continuous vibration in the metallic material. This continuous vibration is measured with a transducer, an amplifier, and a damping factor calculated with a computer as in the first method.

Abstract: The fatigue integrity of metallic materials may be determined by either one of two methods. In a first method, an impulse of energy is introduced into the metallic material, such as by striking the metallic material, and the induced vibration is sensed and analyzed in order to compute the damping factor thereof, the damping factor being directly related to the fatigue thereof. With this method, a transducer is coupled to the metallic material and its output is amplified by an amplifier before input to a computer which determines the damping factor. In a second method, a continuous energy input is provided to the metallic material, such as by utilizing a frequency generator coupled to a power amplifier whose output drives a transducer such as a speaker or the like for inducing a continuous vibration in the metallic material. This continuous vibration is measured with a transducer, an amplifier, and a damping factor calculated with a computer as in the first method.

Abstract: The integrity (density) of discrete pieces of hard tissue (bones) in a patient may be determined by either one of two methods. In a first method, an impulse of energy is introduced into the hard tissue, such as by striking the patient's hard tissue, and the induced vibration is sensed and analyzed in order to compute the damping factor thereof, the damping factor being directly related to the density thereof. With this method, a transducer is coupled to the hard tissue and its output is amplified by an amplifier before input to a computer which determines the damping factor. In a second method, a continuous energy input is provided to the hard tissue, such as by utilizing a frequency generator coupled to a power amplifier whose output drives a transducer such as a speaker or the like for inducing a continuous vibration in the hard tissue. This continuous vibration is measured with a transducer, having amplified output, and a damping factor is calculated with a computer.