空气垫在受到跌落冲击时的缓冲机理及性能研究
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摘要
空气垫是一种新型的缓冲材料,它是由塑料薄膜包裹气体而成。从原理上讲,空气垫是利用密闭在塑料薄膜内的可压缩气体来实现弹性功能。作为缓冲材料,空气垫具有良好的抗冲击性和隔振性。
本文研究了空气垫的几何特征,并根据已有的圆柱模型,得到相应的改进模型。通过准静态压缩试验和模拟跌落试验讨论两种模型的可行性。另外,还进一步研究了空气垫的设计参数对其性能的影响。
本文首先研究了空气垫承受的临界内压、单向阀强度、以及空气垫厚度的相互关系,并通过对单向阀的剥离试验以及空气垫准静态压缩试验,发现空气垫可承受的最大内压随其尺寸的减小而增大。然后通过对空气垫的几何形状进行近似,得到其承载性能的理论模型,并由此发现空气垫的有效承压面积与压缩量基本呈线性关系。在准静态压缩过程中,圆柱模型适合表征尺寸小的空气垫;圆柱改进模型则适合表征尺寸大的空气垫。在冲击压缩过程中,两种模型都可以较好的表征空气垫在压缩时的动态载荷特性,不过当压缩量过大时,理论模型会过高估计空气垫的承载能力;在预测空气垫的动态缓冲能力时,根据改进模型计算出来的理论值与试验值,以及其变化规律更加接近。另外,空气垫薄膜变形对静态压缩的影响不明显;但是对动态压缩存在一定的影响。
关于空气垫的缓冲性能,在准静态压缩变形中,初始内压的增加会使得其缓冲系数减小,但是当初始内压超过60kPa,其减小程度并不明显;最小缓冲系数多发生在应变为0.4～0.6时,其最小值介于2.5～3之间;而尺寸对其静态缓冲性能的影响不大。在动态压缩变形中,随着空气垫初始内压的增大,其动态缓冲性能增强。对于60-115和40-115的空气垫,当重块质量增加时,最大加速度呈增大的趋势;对于30-115的空气垫,最大加速度有先变小,后增大的趋势。
最后,根据空气垫的动态缓冲性能,对产品进行缓冲包装设计,并对六步法中的第四步进行一定的修改,提出使用Gm～n曲线来进行设计,得到所需空气垫规格,以及内包装的尺寸。
Airbag, as a novel air cushioning material, is made of plastic bag filled with gas. And its cushion property is provided by the gas filled in sealed chambers, which gives it lots of advantages both in shock absorption and vibration isolation.
In this paper, an existing geometry model which treated the airbag as a horizontal cylinder was used to study the geometry property of the airbag, while an improved model was proposed then. Both the equivalent static compression and simulated dropping test were employed to validate the applicability of those two models. After that, the cushion properties of the airbag and the effect of the designing parameters on those properties were discussed thereafter.
At first, the relationship among the maximum internal pressure of the airbag, the strength of the check valve and the thickness of the airbag was evaluated by using the peel test of the check valve and the burst test of the airbag. It is found that the maximum pressure increases as the thickness decreases. And then, both geometry models were analyzed, which led several results. The contact area of the airbag grew with the increase of the deflection linearly. In the equivalent static compression, horizontal cylinder model was more suitable for the small size airbag and the improved the larger. And so did the results in the simulated dropping test. While the deflection exceeded to some extent, the theoretic value overestimated the loading property of the airbag. In predicting its dynamic cushion property, the improved model was more suitable by comparing the test and theoretic value. In addition, the distortion of the film was taken into account, which showed that the effect of the film was only concerned in the dynamic test.
At second, the cushion property of the airbag was evaluated. In the equivalent static compression, the cushion coefficient decreased as the initial pressure grew. But when the pressure exceeded 60kPa, the trend for the decrease was slowed. And the minimum cushion coefficient always happened between the value of 2.5~3, when the strain of the airbag was of 0.4~0.6. The effect of initial geometry was not obvious. In the simulated dropping test, the cushion property was strengthened as the initial pressure grew. When the dropping mass grew, the maximum acceleration increased for 60-115, and 40-115. For 30-115, the maximum acceleration decrease at first, and then increased.
In the end, after evaluating the cushion properties, a method was proposed to make the 6-step-method of the traditional cushion package design more suitable for the employment of the airbag. In this manner, the 4th step was optimized, in which Gm～n curve was used to assist the design of the air cushioning packaging.
本文研究了空气垫的几何特征,并根据已有的圆柱模型,得到相应的改进模型。通过准静态压缩试验和模拟跌落试验讨论两种模型的可行性。另外,还进一步研究了空气垫的设计参数对其性能的影响。
本文首先研究了空气垫承受的临界内压、单向阀强度、以及空气垫厚度的相互关系,并通过对单向阀的剥离试验以及空气垫准静态压缩试验,发现空气垫可承受的最大内压随其尺寸的减小而增大。然后通过对空气垫的几何形状进行近似,得到其承载性能的理论模型,并由此发现空气垫的有效承压面积与压缩量基本呈线性关系。在准静态压缩过程中,圆柱模型适合表征尺寸小的空气垫;圆柱改进模型则适合表征尺寸大的空气垫。在冲击压缩过程中,两种模型都可以较好的表征空气垫在压缩时的动态载荷特性,不过当压缩量过大时,理论模型会过高估计空气垫的承载能力;在预测空气垫的动态缓冲能力时,根据改进模型计算出来的理论值与试验值,以及其变化规律更加接近。另外,空气垫薄膜变形对静态压缩的影响不明显;但是对动态压缩存在一定的影响。
关于空气垫的缓冲性能,在准静态压缩变形中,初始内压的增加会使得其缓冲系数减小,但是当初始内压超过60kPa,其减小程度并不明显;最小缓冲系数多发生在应变为0.4～0.6时,其最小值介于2.5～3之间;而尺寸对其静态缓冲性能的影响不大。在动态压缩变形中,随着空气垫初始内压的增大,其动态缓冲性能增强。对于60-115和40-115的空气垫,当重块质量增加时,最大加速度呈增大的趋势;对于30-115的空气垫,最大加速度有先变小,后增大的趋势。
最后,根据空气垫的动态缓冲性能,对产品进行缓冲包装设计,并对六步法中的第四步进行一定的修改,提出使用Gm～n曲线来进行设计,得到所需空气垫规格,以及内包装的尺寸。
Airbag, as a novel air cushioning material, is made of plastic bag filled with gas. And its cushion property is provided by the gas filled in sealed chambers, which gives it lots of advantages both in shock absorption and vibration isolation.
In this paper, an existing geometry model which treated the airbag as a horizontal cylinder was used to study the geometry property of the airbag, while an improved model was proposed then. Both the equivalent static compression and simulated dropping test were employed to validate the applicability of those two models. After that, the cushion properties of the airbag and the effect of the designing parameters on those properties were discussed thereafter.
At first, the relationship among the maximum internal pressure of the airbag, the strength of the check valve and the thickness of the airbag was evaluated by using the peel test of the check valve and the burst test of the airbag. It is found that the maximum pressure increases as the thickness decreases. And then, both geometry models were analyzed, which led several results. The contact area of the airbag grew with the increase of the deflection linearly. In the equivalent static compression, horizontal cylinder model was more suitable for the small size airbag and the improved the larger. And so did the results in the simulated dropping test. While the deflection exceeded to some extent, the theoretic value overestimated the loading property of the airbag. In predicting its dynamic cushion property, the improved model was more suitable by comparing the test and theoretic value. In addition, the distortion of the film was taken into account, which showed that the effect of the film was only concerned in the dynamic test.
At second, the cushion property of the airbag was evaluated. In the equivalent static compression, the cushion coefficient decreased as the initial pressure grew. But when the pressure exceeded 60kPa, the trend for the decrease was slowed. And the minimum cushion coefficient always happened between the value of 2.5~3, when the strain of the airbag was of 0.4~0.6. The effect of initial geometry was not obvious. In the simulated dropping test, the cushion property was strengthened as the initial pressure grew. When the dropping mass grew, the maximum acceleration increased for 60-115, and 40-115. For 30-115, the maximum acceleration decrease at first, and then increased.
In the end, after evaluating the cushion properties, a method was proposed to make the 6-step-method of the traditional cushion package design more suitable for the employment of the airbag. In this manner, the 4th step was optimized, in which Gm～n curve was used to assist the design of the air cushioning packaging.
引文
1. Matlock H, Ripperger E A, Turnbow J W, et al. Energy-absorbing materials and system. Part II [R]. Structural Mechanics Research Laboratory. The University of Texas, Aug. 1957
2. Matlock H, Thompson J N. Preliminary tests on the Non-Pressurized air bag [R]. Structural Mechanics Research Laboratory. The University of Texas, Oct. 1957
3. Turnbow J W, Ogletree W B. The Energy-dissipating characteristics of airbags. Part III [R]. Structural Mechanics Research Laboratory. The University of Texas, Aug. 1959
4. Esgar J B, Morgan W C. Analytical study of soft landing on gas-filled bags [R]. NASA TR R 75. 1960
5. Jogn Thomas Howe. Theory of high-speed-impact attenuation by gas bag [R]. NASA, Technical Note D-1298. 1962
6. F. J. Stimler. Dem Demonstration of procedure for designing impact-bag attenuation systems with predictable performance [J]. Aircraft 1977, 14 (5): 502-507
7. C. Erin, B. Wilson. An improved model of a Pneumatic vibration isolator: theory and experiment [J]. Journal of Sound and Vibration 1998, 218(1), 81-101
8.万志敏,王莉,谢志明等.缓冲气囊的特征气压[J].力学与实践,1998, 20:18-20
9.戈嗣诚,施允涛.无人机回收气囊缓冲特性研究[J].南京航空航天大学学报,1999, 31(4):458-462
10.李芾,付茂海,黄运华.空气弹簧动力学特性参数分析[J].西南交通大学学报,2003, 38(3):276-281
11.黄映云,吴善跃,朱石坚.囊式空气弹簧隔振器的特性计算研究[J].振动工程学报,2004,17(2):249-252
12.刘增华,李芾,傅茂海等.空气弹簧的刚度及阻尼特性研究[J].机车电传动,2005(4):16-19
13.吴善跃,朱石坚,黄映云.带辅助气室橡胶空气弹簧的冲击特性分析[J].振动工程学报,2005,18(2):248-251
14.朱若燕,李厚民,黄映云.圆筒形囊式隔振器静态和动态特性研究[J].工具技术,2006,40(1):23-26
15.吴善跃,黄映云,朱石坚.空气弹簧冲击载荷特性的试验研究[J].振动与冲击,2006,25(2):113-116
16. Y Lino. Air-Cushioning Material from JSP [J]. JPI Journal, 1988, 26 (12): 1274-1275
17. S Minoguchi. Air Bubble Sheet in Shrink Packaging [J]. JPI Journal, 1989, 27 (4): 479-483
18. H. Yamashiro. Cushion Filler TRICONE [J]. JPI Journal, 1989, 27 (2): 291-294
19. T. Mitsuda. Characteristics of the AIR CHAIN for Package design [J]. JPI Journal, 1991, 29 (12): 1345-1351
20. T. Arai, M. Kono.“SOFTECH”A Brand New Shock Absorbing Material [J]. JPI Journal, 1993, 31 (8), 891-897
21. K. Nakagawa. Application of Air-Cushioning Material AIR CHAIN [J]. JPI Journal, 1993, 31 (8): 884-890
22. Takahashi. Development of Environment-Friendly Cushioning Materials [J]. JPI Journal, 1997, 35 (2): 166-173
23. K. Saito, New Air-Cushioning Material [J]. JPI Journal, 1998, 36 (10): 1010-1016
24. Haruo Sasaki, Kaku Saito, et al. Development of an Air Cushioning Material Based on a Novel Idea [J], Packaging Technology Science, 1999; 12: 143-150
25. T. Kitamura, ACP: Reusable Film Packaging [J], JPI Journal, 2003, 41 (4), 308-311
26.郑小林,郑百哲,任力强.气垫性能及平板玻璃缓冲包装[J].包装工程,1991,12(2):62-64
27.郝喜海,马力,唐芬南等.新型绿色缓冲包装材料及生产设备的研究[J].中国包装工业,2000(7):33-36
28.刘占胜,宋海燕,李光等.洗碗机的缓冲包装[J].中国包装,2004(1):97-98
29.刘功,宋海燕,刘占胜等.空气垫缓冲包装性能的研究[J].包装与食品机械,2005,23(2):18-20
30.傅静芳.充气垫作为小型家电缓冲包装的可行性研究[J].包装工程,2005,26(5):35-36
31. New package system [EB/OL]. http://www.esdjournal.com/techpapr/twenty1/new.doc, 2002-11-26
32. Stephen Franks. Calculating factors of safety for package burst and creep test fixtures [EB/OL]. http://www.devicelink.com/mddi/archive/98/01/028.html, 1998
33. Feliú-Báez R. Correlation of Peel and Burst Tests for Pouches [J]. Packag. Technol. Sci, 2001, 14: 63-69
34. Feliú-Báez R. , Hugh E. Lockhart. Effect of Plate Separation on Restrained Burst Test [J]. Packag. Technol. Sci, 2003, 16: 191-198
35. Tanaka et al. Sealing method and apparatus for fluid container [P]. US Patent No. 6,827,099, B2, 2003-6-10
36. Tanaka et al. Structure of air-packing device [P]. US Patent No. 7,165,677 B2. 2004-8-10
37. Fanfu Li, Diana Tweda, James W Goff. Method for deriving the correlation between free fall and shock machine drop height [J]. Packag. Technol. Sci, 1993, 6: 139-146
38. ASTM Standard D 5487. Standard test method for simulated drop of loaded containers by Shock Machines [S], 2002
39. William I Kipp. Shock, drop, and impact testing equivalence [EB/OL]. http://www.kippllc.com/Shock%20Test%20Equiv.pdf, 2002
40. ASTM Standard D 1596-97. Standard test method for dynamic shock cushioning characteristics of packaging material [S], 2003
41. ASTM Standard F 88-06. Standard test method for seal strength of flexible barrier materials [S], 2006
42.彭国勋.物流运输包装设计[M].北京:印刷工业出版社,2006.9
43.汪志诚.热力学·统计物理[M]:第二版.北京:高等教育出版社,1980
44. GB 8168-87包装用缓冲材料静态压缩试验方法[S]. 1987
45. GB 8167-87包装用缓冲材料动态压缩试验方法[S]. 1987
2. Matlock H, Thompson J N. Preliminary tests on the Non-Pressurized air bag [R]. Structural Mechanics Research Laboratory. The University of Texas, Oct. 1957
3. Turnbow J W, Ogletree W B. The Energy-dissipating characteristics of airbags. Part III [R]. Structural Mechanics Research Laboratory. The University of Texas, Aug. 1959
4. Esgar J B, Morgan W C. Analytical study of soft landing on gas-filled bags [R]. NASA TR R 75. 1960
5. Jogn Thomas Howe. Theory of high-speed-impact attenuation by gas bag [R]. NASA, Technical Note D-1298. 1962
6. F. J. Stimler. Dem Demonstration of procedure for designing impact-bag attenuation systems with predictable performance [J]. Aircraft 1977, 14 (5): 502-507
7. C. Erin, B. Wilson. An improved model of a Pneumatic vibration isolator: theory and experiment [J]. Journal of Sound and Vibration 1998, 218(1), 81-101
8.万志敏,王莉,谢志明等.缓冲气囊的特征气压[J].力学与实践,1998, 20:18-20
9.戈嗣诚,施允涛.无人机回收气囊缓冲特性研究[J].南京航空航天大学学报,1999, 31(4):458-462
10.李芾,付茂海,黄运华.空气弹簧动力学特性参数分析[J].西南交通大学学报,2003, 38(3):276-281
11.黄映云,吴善跃,朱石坚.囊式空气弹簧隔振器的特性计算研究[J].振动工程学报,2004,17(2):249-252
12.刘增华,李芾,傅茂海等.空气弹簧的刚度及阻尼特性研究[J].机车电传动,2005(4):16-19
13.吴善跃,朱石坚,黄映云.带辅助气室橡胶空气弹簧的冲击特性分析[J].振动工程学报,2005,18(2):248-251
14.朱若燕,李厚民,黄映云.圆筒形囊式隔振器静态和动态特性研究[J].工具技术,2006,40(1):23-26
15.吴善跃,黄映云,朱石坚.空气弹簧冲击载荷特性的试验研究[J].振动与冲击,2006,25(2):113-116
16. Y Lino. Air-Cushioning Material from JSP [J]. JPI Journal, 1988, 26 (12): 1274-1275
17. S Minoguchi. Air Bubble Sheet in Shrink Packaging [J]. JPI Journal, 1989, 27 (4): 479-483
18. H. Yamashiro. Cushion Filler TRICONE [J]. JPI Journal, 1989, 27 (2): 291-294
19. T. Mitsuda. Characteristics of the AIR CHAIN for Package design [J]. JPI Journal, 1991, 29 (12): 1345-1351
20. T. Arai, M. Kono.“SOFTECH”A Brand New Shock Absorbing Material [J]. JPI Journal, 1993, 31 (8), 891-897
21. K. Nakagawa. Application of Air-Cushioning Material AIR CHAIN [J]. JPI Journal, 1993, 31 (8): 884-890
22. Takahashi. Development of Environment-Friendly Cushioning Materials [J]. JPI Journal, 1997, 35 (2): 166-173
23. K. Saito, New Air-Cushioning Material [J]. JPI Journal, 1998, 36 (10): 1010-1016
24. Haruo Sasaki, Kaku Saito, et al. Development of an Air Cushioning Material Based on a Novel Idea [J], Packaging Technology Science, 1999; 12: 143-150
25. T. Kitamura, ACP: Reusable Film Packaging [J], JPI Journal, 2003, 41 (4), 308-311
26.郑小林,郑百哲,任力强.气垫性能及平板玻璃缓冲包装[J].包装工程,1991,12(2):62-64
27.郝喜海,马力,唐芬南等.新型绿色缓冲包装材料及生产设备的研究[J].中国包装工业,2000(7):33-36
28.刘占胜,宋海燕,李光等.洗碗机的缓冲包装[J].中国包装,2004(1):97-98
29.刘功,宋海燕,刘占胜等.空气垫缓冲包装性能的研究[J].包装与食品机械,2005,23(2):18-20
30.傅静芳.充气垫作为小型家电缓冲包装的可行性研究[J].包装工程,2005,26(5):35-36
31. New package system [EB/OL]. http://www.esdjournal.com/techpapr/twenty1/new.doc, 2002-11-26
32. Stephen Franks. Calculating factors of safety for package burst and creep test fixtures [EB/OL]. http://www.devicelink.com/mddi/archive/98/01/028.html, 1998
33. Feliú-Báez R. Correlation of Peel and Burst Tests for Pouches [J]. Packag. Technol. Sci, 2001, 14: 63-69
34. Feliú-Báez R. , Hugh E. Lockhart. Effect of Plate Separation on Restrained Burst Test [J]. Packag. Technol. Sci, 2003, 16: 191-198
35. Tanaka et al. Sealing method and apparatus for fluid container [P]. US Patent No. 6,827,099, B2, 2003-6-10
36. Tanaka et al. Structure of air-packing device [P]. US Patent No. 7,165,677 B2. 2004-8-10
37. Fanfu Li, Diana Tweda, James W Goff. Method for deriving the correlation between free fall and shock machine drop height [J]. Packag. Technol. Sci, 1993, 6: 139-146
38. ASTM Standard D 5487. Standard test method for simulated drop of loaded containers by Shock Machines [S], 2002
39. William I Kipp. Shock, drop, and impact testing equivalence [EB/OL]. http://www.kippllc.com/Shock%20Test%20Equiv.pdf, 2002
40. ASTM Standard D 1596-97. Standard test method for dynamic shock cushioning characteristics of packaging material [S], 2003
41. ASTM Standard F 88-06. Standard test method for seal strength of flexible barrier materials [S], 2006
42.彭国勋.物流运输包装设计[M].北京:印刷工业出版社,2006.9
43.汪志诚.热力学·统计物理[M]:第二版.北京:高等教育出版社,1980
44. GB 8168-87包装用缓冲材料静态压缩试验方法[S]. 1987
45. GB 8167-87包装用缓冲材料动态压缩试验方法[S]. 1987
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