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BIOMOMENTUM力學試驗機--人發機械性能評估
閱讀：289 發布時間：2021-3-16BIOMOMENTUM力學試驗機--人發機械性能評估
EVALUATION OF THE MECHANICAL PROPERTIES OF HUMAN HAIR
We were recently asked if our mechanical tester has the capability of evaluating the mechanical properties of single fiber human hair. In our lab, a scientist has been devoted to this feasibility study.
The hardest part of this work was to develop the proper gripping fixtures to easily mount the hair on the tester to be able to perform tensile and torsion testing. Following few attempts, it was found that the simplest and most reproducible mounting method was based on the use of a pair of off-the-shelf syringe needle tips. On the bench, the hair fiber was inserted through the two needles facing each other and spaced by a predefined gauge gap. A single drop of cyanoacrylate glue was applied in the plastic cavity of each needle to secure the hair in place. Two needle tip holders with the same tapered shape as a regular syringe were mounted on the Mach-1. These two holders were fastened facing each other at the center of a testing chamber under a 17N multiaxis load cell. The double-needle hair assembly was then firmly inserted over the holder (see Image 1).
After zeroing the load, and considering the relative position of the vertical stage, the initial length of the hair at full extension (when no load is applied) was measured using the Mach-1 Motion's "Find Contact" function. A sinusoidal deformation in the elastic region was applied for 30 cycles at 0.5, 1 and 2 Hz. A Dynamic Mechanical Testing analysis was conducted as per MA056-SOP04-D to extract the complex tensile storage and loss modulus components. Dynamic testing showed an increase in phase magnitude with increased frequency. This result was expected and explains an increase in plastic deformation (loss modulus) with increased frequency.
The tensile modulus and ultimate tensile strength were also measured and calculated (Mach-1 Analysis software) during a tensile load ramp to failure (see Image 2 - Tensile test output until failure). The results were found to be in accordance with literature (Lee, 2012): 930 MPa ultimate tensile strength, 6.5 GPa elastic modulus. Other tests were completed using a rotational stage to apply torsion to the hair until rupture occurred. For two samples, the results were 175 and 179 turns before failure. A camera feed with a 10X lens was used to visualize the torsion of the fiber in real time.
The plastic torsion of the hair remains even after breakage and can be visualized under a microscope (see Image 3 - Post-torsion photograph using 20x microscope).
During torsion, the generated torque around the Z-axis was too low to be measured by the 17N multiaxial load cell. However, the vertical contraction of the hair induced by torsion created a vertical contractile force that was measured by the Fz channel of the cell. It is assumed that through proper theoretical modelling of this test configuration, this axial load could be used to indirectly measure the torsional shear strength of the hair.
Different indirect ways of quantifying the torsional properties of fibres have also been proposed in literature. For example, by relating the initial gauge length to the number of rotations before rupture, a theoretical value for fracture angle can be obtained. From a basic analysis, the fracture angle was found to be between 26 and 33°.
近，我們被問到我們的機械測試儀是否具有評估單纖維人發機械性能的能力。在我們的實驗室中，一位科學家致力于這項可行性研究。
這項工作困難的部分是開發合適的抓持裝置，以將頭發輕松安裝到測試儀上，以執行拉伸和扭轉測試。經過幾次嘗試，發現簡單，可重復的安裝方法是基于使用一對現成的注射器針尖。在工作臺上，將毛發纖維穿過彼此面對的兩個針頭插入，并以預定的標尺間隙隔開。將一滴氰基丙烯酸酯膠滴到每個針的塑料腔中，以將頭發固定到位。在Mach-1上安裝了兩個具有與普通注射器相同的錐形形狀的針尖支架。將這兩個支架在17N多軸稱重傳感器下的測試腔室中心彼此相對固定。
將負載歸零后，考慮垂直臺的相對位置，使用Mach-1 Motion的“查找接觸”功能測量在*伸展時（未施加負載時）頭發的初始長度。在彈性區域以0.5、1和2 Hz的頻率施加正弦形變形30個循環。根據MA056-SOP04-D進行動態力學測試分析，以提取復雜的拉伸存儲和損耗模量分量。動態測試顯示相位幅度隨頻率增加而增加。該結果是預期的，并解釋了塑性變形（損耗模量）隨頻率增加而增加。
biomomentum多軸機械測試儀Mach-1
Mach-1多軸機械測試儀是模塊化集成壓縮，拉伸，剪切，摩擦，扭轉和3D壓痕映射、電位分布等測試設備
biomomentum至1999年以來，專注用于測試生物材料，組織和關節軟骨機-電特性產品的設計、開發、制造和商業化的創新解決方案20余年。
其mach-1多軸向多功能組織材料機械特性測試分析系統已經成為組織材料機械-電位測試分析的黃金標準。
1、多功能、多軸向，適用樣品范圍廣：
•1.1、從骨等硬組織材料到腦組織、眼角膜等極軟的組織材料
•1.2、從粗的椎間盤的樣品到極細的單纖維絲
2、力學類型測試分析功能齊全：
2.1、模塊化集成壓縮、張力、剪切、摩擦、扭轉、穿刺、摩擦和非平面壓痕、3D厚度、3D表面輪廓等各種力學類型支持,微觀結構表征及動態力學分析研究
2.2、多物理場耦合加載測試
•3、通高量壓痕、壓縮測試分析（48孔板中壓痕測試分析）
•4、高精度、高分辨率:
•4.1、位移分辨率達0.1um
•4.2、力分辨率達0.025mN
•4.3、樣品直徑小25um
•5、行程范圍廣：50-250mm
•6、體積小巧、可放入培養箱內
•7 、DIC （Digital Image Correlation)數字圖像相關法非接觸式的高精度位移、應變測量
•9、活性組織電位分布測試分析
•10、產品成熟，文獻量達上千篇
biomomentum多軸機械測試儀Mach-1材料力學性能簡介：
biomomentum多軸機械測試儀Mach-1材料力學性能是指材料在不同環境(溫度、介質、濕度)下，承受各種外加載荷(拉伸、壓縮、彎曲、扭轉、沖擊、交變應力等)時所表現出的力學特征。
可以放進標準培養箱里進行培養；
biomomentum多軸機械測試儀Mach-1測試意義及適用范圍：
材料力學性能可以應用到生產的任何階段，從測試原材料質量直到檢查制成品的耐用性。 測試可對廣泛多樣的生物樣品、材料和產品進行，包括軟組織、軟骨組織、皮膚組織、凝膠組織、高分子材料、生物產品、醫學鑒定和水凝膠等。力學性能測試可幫助企業向客戶證明其產品的力學性能、穩定性和安性，從而獲得基礎數據和競爭勢。
1、多功能、多軸向，適用樣品范圍廣：
1.1、從骨等硬組織材料到腦組織、眼角膜等極軟的組織材料
1.2、從粗的椎間盤的樣品到極細的單纖維絲
2、力學類型測試分析功能齊全：
2.1、模塊化集成壓縮、張力、剪切、摩擦、扭轉、穿刺、摩擦和非平面壓痕、3D厚度、3D表面輪廓等各種力學類型支持,微觀結構表征及動態力學分析研究
2.2、多物理場耦合加載測試