1) The document discusses modeling fiber-reinforced membrane materials using continuum mechanics. Two tasks are presented: modeling the stresses in a textile membrane used in lightweight roof constructions, and modeling stresses in the aorta under blood pressure.
2) The model uses a strain energy potential that accounts for the isotropic matrix and transversely isotropic behavior of the fiber reinforcement. Boundary conditions and simplifying assumptions are applied to solve for the relevant stresses and strains.
3) In the first task, the model is applied to a textile membrane under external pressure to solve for hoop and axial stresses and strains. In the second task, the same approach is used to model stresses in the aorta wall under blood pressure and compare
Presentation of the MOOC@TU9 course "Discover Excellence in Engineering and the Natural Sciences - Made in Germany. Discover TU9!" on the 17th Annual Colloquium on International Engineering: Education: New Frontiers.
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Lecture 1 MOOC@TU9: Entrepreneurship by Prof. Brettelmooctu9
Do you want to acquire information about entrepreneurship research at the RWTH Aachen?
Here you get insights into the entrepreneurial development of the Streetscooter!
First order shear deformation (FSDT) theory for laminated composite beams is used to study free vibration of
laminated composite beams, and finite element method (FEM) is employed to obtain numerical solution of the
governing differential equations. Free vibration analysis of laminated beams with rectangular cross – section for
various combinations of end conditions is studied. To verify the accuracy of the present method, the frequency
parameters are evaluated and compared with previous work available in the literature. The good agreement with
other available data demonstrates the capability and reliability of the finite element method and the adopted beam
model used.
Presentation of the MOOC@TU9 course "Discover Excellence in Engineering and the Natural Sciences - Made in Germany. Discover TU9!" on the 17th Annual Colloquium on International Engineering: Education: New Frontiers.
Join the course for free on: http://mooc.tu.de
Lecture 1 MOOC@TU9: Entrepreneurship by Prof. Brettelmooctu9
Do you want to acquire information about entrepreneurship research at the RWTH Aachen?
Here you get insights into the entrepreneurial development of the Streetscooter!
First order shear deformation (FSDT) theory for laminated composite beams is used to study free vibration of
laminated composite beams, and finite element method (FEM) is employed to obtain numerical solution of the
governing differential equations. Free vibration analysis of laminated beams with rectangular cross – section for
various combinations of end conditions is studied. To verify the accuracy of the present method, the frequency
parameters are evaluated and compared with previous work available in the literature. The good agreement with
other available data demonstrates the capability and reliability of the finite element method and the adopted beam
model used.
Sliding motion and adhesion control through magnetic domaminsAndrea Benassi
Actuation and control of motion in micro mechanical systems are technological challenges, since they are accompanied by mechanical friction and wear, principal and well known sources of device lifetime reduction. In this theoretical work we propose a non-contact motion control technique based on the introduction of a tunable magnetic interaction. The latter is realized by coating two non-touching sliding bodies with ferromagnetic films. The resulting dynamics is determined by shape, size and ordering of magnetic domains arising in the films below the Curie temperature. We demonstrate that the domain behavior can be tailored by acting on handles like ferromagnetic coating preparation, external magnetic fields and the finite distance between the plates. In this way, motion control can be achieved without mechanical contact. Moreover, we discuss how such handles can disclose a variety of sliding regimes. Finally, we propose how to practically implement the proposed model sliding system.
TRANSIENT ANALYSIS OF PIEZOLAMINATED COMPOSITE PLATES USING HSDTP singh
Piezoelectric materials have excellent sensing and actuating capabilities have made them the most practical smart materials to integrate with laminated structures. Integrated structure system can be called a smart structure because of its ability to perform self-diagnosis and quick adaption to environment changes. An analytical procedure has been developed in the work based on higher order shear deformation theory subjected to electromechanical loading for investigating transient characteristics of smart material plates. For analysis two displacement models are to be considered i.e., model-1 accounts for strain in thickness direction is zero whereas in model-2 in-plane displacements are expanded as cubic functions of the thickness coordinate. Navier’s technique has been adopted for obtaining solutions of anti-symmetric cross–ply and angle-ply laminates of both model-1 and model-2 with simply supported boundary conditions. For obtaining transient response of a laminated composite plate attached with piezoelectric layer Newmark’s method has been used. Effect of thickness coordinate of composite laminated plates attached with piezoelectric layer subjected to electromechanical loadings is studied.
“Investigation of Structural Analysis of Composite Beam Having I- Cross Secti...IOSR Journals
Abstract: - In structural applications, beam is one of the most common structural members that have been
considered in design. This paper is intended to provide tools that ensure better designing options for composite
laminates of I -beam. In this Paper an analytical method & FEM approach calculating axial stiffness , Axial
stress ,Axial strain of flange and web laminates. The results show the stacking sequence and fiber angle
orientation strongly affects strength of composite I-beam.
Dynamic Behavior of Fiber Reinforced Composite Beam With CrackIJMERJOURNAL
ABSTRACT: Composites have numerous applications in engineering field. In engineering design averting failure of composite material system has been a vital concern. Composite are subjected to numerous types of damage, mostly cracks and delamination. The presence of crack causes a variation in stiffness and it also affects the mechanical behavior of entire structure. Cracks are caused by fatigue under service conditions as a consequence of limited fatigue strength. Measurement of natural frequency can be taken as a tool to identify the presence of cracks which are propagated due to fluctuating stress conditions. In the present work an attempt has been made to find the natural frequencies of fiber reinforced composite cantilever beams with and without presence of a transverse surface crack. E-Glass fiber reinforced composite beams with epoxy resin having a volume fraction of 16.6% have been casted by hand lay-up method and are used for determination of natural frequencies of beams. The free vibration study is carried out by ATALON FFT analyzer, accelerometer and excitation by impact hammer. The DEWESOFT software is used to convert the responses from time domain to frequency domain and the Frequency Response Functions (FRF) are obtained. The experimental results are compared with numerical predictions using the FEM based software package ANSYS 16.2. The process of finding of natural frequencies is carried out for various crack depth ratios at various crack locations by both numerical and experimental methods. A good accord is observed between the experimental and ANSYS results.
My research at Boston University (May 2013)
1. Thesis: Viscoelastic testing and modeling of PDMS micropillars for cellular force measurement
2. Side Projects
1) Conducting polymer actuators
2) PDMS and conducting polymer nanowire composites
3) Silicon oxycarbide thin films
4) Tribological study of DLC coatings
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Similar to Slides presentation modeling_fiberreinforced_membran_materials (20)
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MOOCs als Instrument des hochschulübergreifenden Marketings und der Studienor...mooctu9
Präsentation im Rahmen der Tagung "E-Learning Strategien an Hochschulen", Forum Neue Medien Austria (fnm-a), Universität Salzburg, 05.05.2015
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Präsentation von MOOC@TU9 auf im Rahmen des Seminars "Das Potenzial von MOOCs für die Internationalisierung" der internationalen DAAD-Akademie, 25.11.2014, Bonn
1. Fakult¨at Bauingenieurwesen Institut f¨ur Mechanik und Fl¨achentragwerke
Modeling of Fiber-Reinforced Membrane Materials
Daniel Balzani
Faculty of Civil Engineering, Institute of Mechanics and Shell Structures
Acknowledgement: Anna Zahn
• Introduction / Motivation
• Continuum Mechanical Preliminaries
• Task 1: Textile Membrane of a Lightweight Structure
• Task 2: Aorta under Physiological Blood Pressure
2. Motivation: Fiber-Reinforced Materials
Engineering applications
• Light-weight roof constructions
• Facade cover design
• Weather-proof awnings
Roof construction at the ATP
tournement in Indian Wells
Roof construction of Dresden
main station
Textile membranes
• Composite material
• Woven network of stiff fibers
• Soft and isotropic matrix material
Soft biological tissues
• Conceptionally similar material composition
• Collagen fibers reinforce an isotropic ground substance
c Prof. Dr.-Ing. habil. D. Balzani, Institut f¨ur Mechanik und Fl¨achentragwerke
3. Continuum Mechanical Preliminaries I
Assumptions
• Idealization as thin membranes
• Small strain framework
• Representation of one fiber reinforcement by
transversely isotropic model; fiber direction a(a) z
ϕ
a(2)
a(1)
t r
Calculation of the stresses
The stress tensor σ can be calculated by the derivative of a strain energy
function ψ(ε) with respect to the classical strain tensor ε:
σ =
∂ψ(ε)
∂ε
(1)
A specific energy function ψ has to be constructed such that the resulting stresses
match experimental data.
c Prof. Dr.-Ing. habil. D. Balzani, Institut f¨ur Mechanik und Fl¨achentragwerke
4. Continuum Mechanical Preliminaries II
Strain energy function
Here, we consider the strain energy function
ψ =
1
2
λ J2
1 + µ J2
ψiso
+
2
a=1
1
2
α(a)
J
(a)
4
2
ψti
(a)
(2)
which is formulated in terms of the basic and mixed invariants
J1 = tr [ε], J2 = tr [ε2
] and J
(a)
4 = tr [εM(a)
]. (3)
The coefficients of the structural tensor M(a)
are
M
(a)
ij = a
(a)
i a
(a)
j , (4)
wherein a
(a)
i are the coefficients of the fiber orientation vectors a(a)
.
c Prof. Dr.-Ing. habil. D. Balzani, Institut f¨ur Mechanik und Fl¨achentragwerke
5. Continuum Mechanical Preliminaries III
Remarks for the solution of the tasks
• The Lam´e constants λ and µ are determined by the Young’s modulus E and
the Poisson ratio ν according to
λ =
Eν
(1 + ν) (1 − 2ν)
and µ =
E
2 (1 + ν)
(5)
• Rotation-symmetric structures are parameterized by polar coordinates (r, ϕ, z)
• Stresses/strains in radial direction are neglected and shear stresses/strains do
not occur
• Summing up these simplifications, 2 of 9 non-trivial equations remain from (1)
σii =
∂ψ(εii)
∂εii
with i ∈ [ϕ, z]. (6)
c Prof. Dr.-Ing. habil. D. Balzani, Institut f¨ur Mechanik und Fl¨achentragwerke
6. Task 1: Textile Membrane of a Lightweight Structure
ϕ
z
z
r
ϕ
pM
rM
tM
a
(2)
M
a
(1)
M
• Using the presented energy function, a system of equations for the unknown
quantities σϕ, σz, εϕ and εz can be determined based on σ = ∂εψ.
• From the boundary conditions we obtain εz = 0 and the stress σϕ can be
calculated from Barlow’s formula,
σϕ = pM
rM
tM
. (7)
• Solve the system of equations for εϕ and σz and compare with the ultimate
values εϕ,max and σz,max.
c Prof. Dr.-Ing. habil. D. Balzani, Institut f¨ur Mechanik und Fl¨achentragwerke
7. Task 2: Aorta under Physiological Blood Pressure
ϕ
z
z
r
ϕ
rA
pA
tA
β
(1)
A
a
(1)
A
β
(2)
A
a
(2)
A
Compared to the air-inflated membrane, the internal pressure of human arteries is
significantly higher and the fiber stiffnesses are relatively low.
• Compute analogously the values for εϕ and σz.
• Although technically impossible, check if the membrane in the roof construction
of Task 1 could be replaced by arterial tissue.
c Prof. Dr.-Ing. habil. D. Balzani, Institut f¨ur Mechanik und Fl¨achentragwerke
8. Have fun!
c Prof. Dr.-Ing. habil. D. Balzani, Institut f¨ur Mechanik und Fl¨achentragwerke