东华大学纤维集合体力学2016期末考试考卷

2016~ 2017学年第 1 学期研究生期末考试试题

考试学院： 纺织学院

考试专业： 修习本课程硕士生

考试课程名称： 纤维集合体力学

（考生注意：答案必须写在答题上，写在本试题纸上一律不给分）

[试题部分]

[注]: 本试卷共计10题，均为必答题。满分100分。

一 (10)

二 (5)

三 (15)

四 (10)

五 (10)

六 (10)

七 (10)

八 (10)

九 (10)

十 (10)

总分

2016~ 2017学年第 1 学期研究生期 末 考试试题 考试学院： 纺织学院 考试专业： 修习本课程硕士生 考试课程名称： 纤维集合体力学

（考生注意：答案必须写在答题上，写在本试题纸上一律不给分）

[试题部分]

1 (10’s)

For a polymer fiber with a constitutive equation as:

∑∑===n

i m

j j j j i i i t b t a 00)()()()(d d d d εσ deriving the elastic, visco, parallel and series visco-elastic equations.

2 (5’s)

Based on the definition of flexible fiber assembly, explain the structure and deformation differences between a knitted fabric and a thin steel aluminum plate.

3 (15’s)

For a non-woven fabric:

(1) Describe the history of the research of the mechanics of non-woven fabric. (5’s)

(2) How to calculate the elastic stiffness along the longitudinal direction both from force method,

energy method and numerical method? (10’s)

Generally, there are near 108 staple fibers in 1m 2 woven fabrics. Given the flowchart from multi-scale structure approach to calculate the ballistic impact damage of woven fabric. 5 (10’s)

(1) When we investigate the fabric drape, how we can predict the fabric drape from artificial

neural networks (ANNs) and finite element method (FEM)? (5’s)

(2) For a wool sweater, how to characterize the fabric-evoked prickle from a single fiber properties both from ANNs and FEM? (5’s)

6 (10’s)

For the Weibull strength theory of parallel filament fiber tow, the stress strain equation is:

)](

[exp(0

m E E σε

εσ-=

where E is Young’s modulus of fiber. Explaining how to obtain the parameters of 0σand m in

experimental.

7 (10’s)

(1) For Fig.1, describe the multi-scale structure of twisted filament yarns and staple yarns. (2) The method to characterize the yarn structure.

Fig.1 Twisted yarn

For the woven fabric drape behavior, how to investigate the drape coefficient and drape shape of a woven fabric in numerical way as shown in Fig.2?

Fig.2 Numerical calculation of woven fabric drape shape

9 (10’s)

(1) A 3-D 4-step braided preform in Fig.3, what’s methodology for deriving the stress-strain behaviors under uni-axial tension? (5’s)

(2) Describe the multi-scale structure of the 3-D 4-step braided preform. (5’s)

Fig.3 Virtual graph of 3-D 4-step braided preform

(1)As shown in Fig.4, explaining the differences of yarn interactions between coated woven

fabric and woven fabric. (5’s)

(2)And also, the differences of bending stiffness. (5’s)

Fig.4 Coated woven fabirc