| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 98 === In this study, the aid is chose experimental methods to probe for soft tissue and gelatin mechanical properties, it would be beneficial to development of endoscopic needle-free injection technology. Using deep penetration test, compression test and tear test methods such as the decision of the mechanical properties of soft solid materials. Deep penetration test are classified according to samples shape; block and thin sheets of soft solid materials, and chose three types punches: sharp-tipped, flat-bottomed cylindrical and spherical-tipped punches, the punch velocity was 3 ~ 120 mm / min, the target of gelatin (30%) and pig colonic tissues were measured mechanical intensity. Pig colon deep penetration test results showed that the stress strain curve consists of five stages: the first stage is fairly linear relationship of strain- stress curve; the second stage, stress increases exponentially with strain; the third stage, stress- strain relationship become linear until the partial rupture occur; the fourth stage, following the partial rupture point, linear relationship between stress and strain; the fifth stage, nonlinear part of the curve until the rupture. In the deep penetration test, stress - strain diagram can be observed the tissue of multi-layer structure. The failure strength measured value is mainly affected by the shape and settling velocity of the punch, The measured breakdown strength values of flat-bottomed punch is the largest, sharp-tipped punch measured value is the smallest and the measurement variance is the minimum. The results also show that when flat-bottomed and spherical-tipped punch-type of the settling velocity increases, the measured failure strength decreases, but the sharp-tipped punch-type failure strength measurement less affected. As the needle-free injection technology is micro-injection, and sharp-tipped punch similar, so sharp-tipped punch measured values can be used for the needle-free injection. Found by calculation, the shape and settling velocity of the punch under the strain range from 0.125 to 0.15, the best linear fitting results, the linear range of the average Young's modulus were 1.5526 ± 0.2119 MPa (flat-bottomed punch), 0.7618 ± 0.2990 MPa (spherical-tipped punch) and 0.7609 ± 0.1976 MPa (sharp-tipped punch). Gelatin (30%) of the block deep penetration test showed that the stress - depth curve and the silicone block typical of deep penetrating curve in literature are similar to the value of the surface rupture strength of the punch used in tandem with the shape varies. Pig colon tissue compression test and tear test results show that the strain range of 0.125 to 0.15 and the average Young's modulus was 0.089 ± 0.0036 MPa and the tear rate of 50 and 100 mm / min, its tear strength was 1.072 ± 0.087 N / mm and 0.796 ± 0.129 N / mm. As the punch shape will affect the measurement results, the difference up to 45% or more, it must be considered when using the experimental data, the fracture mode of application cases, and punch shape caused by the rupture patterns.
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