共查询到18条相似文献,搜索用时 234 毫秒
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通过建立粘扣带单钩剪切力力学模型,推导出整片粘扣带剪切强度力学模型,得到粘扣带剪切强度计算式;按照理论剪切强度相对于实际剪切强度的偏差百分率不大于5%,对单位面积钩的密度、钩挂率、修正系数人为取值,得到粘扣带剪切强度的计算式,即剪切强度与粘扣带钩的直径的关系式。在有限范围内可以用于粘扣带剪切强度的计算和预测。 相似文献
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粘扣带剥离强度力学模型研究 总被引:1,自引:0,他引:1
通过建立粘扣带单钩剥离强力力学模型,推导出整片粘扣带剥离强度力学模型,得到粘扣带剥离强度计算式;按照理论剥离强度相对于实际剥离强度的偏差百分率不大于5%,对单位宽度钩的密度、钩挂率、修正系数人为取值,从而得到粘扣带剥离强度的简单计算式,即剥离强度与粘扣带钩的直径的关系式,在有限范围内可以用于粘扣带剥离强度的计算和预测。 相似文献
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将PEN(聚萘二甲酸乙二醇酯)和PPS(聚苯硫醚)切片共混熔融纺丝,得到耐温性好且可纺性强的共混长丝。为了探究共混比例对长丝性能的影响,将PEN/PPS以100/0、97/3、95/5三种比例(质量比)共混,并对长丝进行力学性能、耐化学性能、耐热性能、热缩率测试。结果表明:PPS的少量添加对PEN长丝的熔点影响不大,但PEN/PPS(95/5)共混长丝的结晶度远远小于其他两种比例的长丝;PEN/PPS(97/3)共混长丝同时具有高强力和高伸长率,且其在170℃热处理下强力变化率低,较为稳定;三种长丝在70℃下都具有较好的耐酸碱性,但PEN/PPS(97/3)共混长丝在90℃的温度下也能维持一定的酸碱稳定性;虽然三种长丝的热收缩率都较高,但PEN/PPS(97/3)共混长丝的收缩率最小。 相似文献
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为研究烟用拉线粘接性能的测试方法,分析了初粘性、持粘性、水平剥离强度、90°剥离强度、180°剥离强度等粘接性能测试方法的基本原理,对水平剥离强度、90°剥离强度和180°剥离强度测试方法进行了比较.结果表明:初粘性、水平剥离强度均不适用于拉线粘接性能的测试;持粘性测试方法需要时间较长,不适宜作为拉线粘接性能优劣的判定手段;180°剥离强度测试结果离散度小,变异系数为3.5%,优于90°剥离强度测试方法,且测试方法科学合理、数据稳定、适用性强,可以作为表征烟用拉线粘接性能的测试方法. 相似文献
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B. Emadi M. H. Abbaspour-Fard P. KDV Yarlagadda 《International Journal of Food Properties》2013,16(4):780-790
Mechanical properties of three common varieties of melon were measured. These are toughness, rupture force, shear strength, maximum shearing force, and cutting force. The role of peel (%) on each property was also calculated as the relative contribution of peel to unpeeled produce. The shear strength of peel was statistically found similar (p > 0.05) for all varieties. The same result was also revealed for unpeeled produce. Using rupture force was not recommended for peeling watermelon, because of close values of this property for its peel and unpeeled case. The required energy for peeling all three varieties of melon was determined to be 500 N mm. Peeling melons using cutter tools could not be recommended. 相似文献
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为解决废旧聚苯硫醚(PPS)滤袋难处理的问题,将其回收进行碱洗处理,再利用热风黏合成形加工方法将碱洗处理的滤袋与不同厚度规格的聚氨酯(PU)膜相结合制备多层吸声复合材料。借助扫描电子显微镜、垂直法阻燃性能测试仪、电子织物强力机、噪声振动测试系统对PPS+PU+PPS与PPS+PU+PPS+PU+PPS 这2种结构形貌特征、阻燃性能、力学性能、吸声隔声性能进行表征。结果表明:碱洗处理的滤袋表面依然残留少量粉尘颗粒,但并未出现纤维破损断裂的现象,纤维间孔隙较多,复合材料纤维间的孔隙减少,内部变得致密;处理后的复合材料,阻燃性能与单层PPS滤料相比,依旧保持较好,在同种结构中,其力学性能均与PU膜厚度呈现正相关;2种结构中,吸声系数呈现出相同的变化趋势,并且大小与膜厚呈现负相关,高频阶段最大可达0.27,传递损失程度与膜厚呈现负相关,PPS+PU+PPS+PU+PPS结构在高频阶段最高可达41 dB。 相似文献
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Adhesion modeling on rough low linear density polyethylene 总被引:1,自引:0,他引:1
ABSTRACT: Food adhesion is an important attribute that could have both positive and negative ramifications depending on the application. Yet, its quantification remains cumbersome and as a consequence adhesion models are scarce. The effect of surface roughness, free energy, and ozone treatment on adhesion of rough low linear density polyethylene films was investigated. Adhesion was measured by a 180° peel strength test. The plastic films were roughened (surface roughness ratio, r , ranged from 1.00 to 1.15). Exposing the film to ozone treatment (0 to 300 s) modified its surface free energy, γ s (32.4 to 37.9 mJ/m2 , respectively), and its polar component of the surface free energy, γ p s (3.0 to 8.3 mJ/m2 , respectively). The films were coated with polyurethane capable of forming hydrogen bonds. Adhesion was found to be a function of the apparent contact angle of water, θ ap [water] , surface roughness ratio, and surface free energy. The linear relationship between the apparent contact angle of water, θ ap [water] , and γ p s was incorporated in building an empirical model that quantifies peel strength as function of r and γ p s . The model showed good agreement with experimental data, especially for longer ozone exposures and rougher surfaces. The empirical model provides insight into the relationships between surface roughness, surface energy, and adhesion. Quantifying these effects could facilitate reducing biofilm forming on food equipment, antisticking treatments, or easy peel packages, or reducing food residues adhering to the food packages and consequently minimize oxidation, off flavors, and waste. 相似文献
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该试验通过对市售的10种含油量高的油性剁辣椒和10种不含油或含油量极低的水性剁辣椒进行全质构分析(TPA),对测试结果与感官评定进行相关性分析,并建立以剁辣椒脆度的感官评分为因变量的回归方程。试验结果发现,剁辣椒的硬度、剪切强度、韧性与剁辣椒的感官评分之间有良好的正相关性,证明剁辣椒的脆性在一定程度上能代表剁辣椒的品质。并对剁辣椒脆度的感官评分与仪器测定的指标进行逐步回归分析,较为准确的计算出当水性剁辣椒硬度>5 719 g,剪切强度>272.8 g,韧性>35.15 g·s时,剁辣椒的脆性非常好;当油性剁辣椒硬度>7 372 g,剪切强度>316.42 g,韧性>44.76 g·s时,剁辣椒的脆性非常好。 相似文献