Measurements of Through-Thickness Young's Moduli of Fibrous Composite Laminates Using Nanoindentation

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
L. Roy Xu ◽  
Ricardo Martinez ◽  
Kai Zhao
Keyword(s):  
Composite Laminates ◽  
Vinyl Ester ◽  
Composite System ◽  
Fibrous Composite ◽  
Approximate Expression ◽  
Material System ◽  
New Approach ◽  
Young’S Moduli ◽  
Reduced Modulus ◽  
Orthotropic Composites

A new approach of measuring through-thickness Young's moduli of composite materials using nanoindentation was proposed. First, an approximate expression of the reduced modulus of nanoindentation was introduced for orthotropic composites. Second, spherical nanoindentation was conducted for an E-glass fiber/vinyl ester composite system, and measured Young's modulus was quite consistent with the previously reported value for a similar material system.

Influence of the stacking sequence on the through-thickness Young’s moduli of fibrous composite laminates measured by nanoindentation

2020 ◽  
pp. 002199832096565
Author(s):  
Luoyu Roy Xu ◽  
Md Mehadi Hassan ◽  
Osman Anderoglu ◽  
Kai Zhao ◽  
Mark Flores
Keyword(s):  
Young’S Modulus ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Young's Modulus ◽  
Fiber Composite ◽  
Fibrous Composite ◽  
Test Procedures ◽  
Young’S Moduli ◽  
Glass Fiber Composite ◽  
Carbon Fiber Epoxy

Previous approaches to measure the through-thickness Young’s modulus of a composite laminate often employed complicated specimens and test procedures, so very few through-thickness Young’s moduli were reported. An efficient spherical nanoindentation approach was developed to measure the through-thickness Young’s moduli of a woven fibric glass-fiber composite laminate. In this paper, the same approach is extended to the modulus measurement of four carbon fiber/epoxy IM7/937-7 laminates with complicated stacking sequences. The measured through-thickness Young’s moduli were consistent with the transverse Young’s modulus of the same composite system. Results show that the stacking sequences have little influence on the through-thickness Young’s moduli, which could be explained by classical lamination theory for a thin composite laminate.

A Model for the Energy Absorption Capability of Composite Laminates

2006 ◽  
Author(s):  
Stefano Mian ◽  
Marino Quaresimin
Keyword(s):  
Composite Laminates ◽  
Master Curve ◽  
Material System ◽  
New Approach ◽  
External Data ◽  
Reinforcing Fibers ◽  
Laminate Thickness ◽  
Definition Of ◽  
Impact Data ◽  
The Impact

A new methodology for the analysis of impact data has been recently proposed [1], based on the definition of two normalised coefficients, the absorption coefficient (ratio of absorbed to penetration energy) and the intensity coefficient (ratio of impact to penetration energy). The new approach allowed the definition of an empirical master curve suitable to summarize the impact data irrespectively of material system, laminate thickness and lay-up. This work is oriented to quantitatively validate the master curve on the basis of experimental impact data previously obtained and other “external” data taken from the open literature, referred to laminates with significant variation of properties in terms of type and architecture of the reinforcing fibers, lay-up and thickness. In spite of the very large number of data collected for the validation, the master curve turned out suitable to describe all the normalized data with a reasonably reduced scatter.

Modeling the Debonding Behavior of Step-Tapered Patches: Analytical Solutions and Numerical Analysis of Selected Structures

1999 ◽  
Author(s):  
A. M. Karlsson
Keyword(s):  
Critical Load ◽  
Composite System ◽  
Sliding Contact ◽  
Material System ◽  
Fiber Reinforced ◽  
Inferior Surface ◽  
Curved Structures ◽  
Weak Part ◽  
Simple Boundary ◽  
Base Structure

Abstract A common method to strengthening or stiffening a weak part of an airplane structure is to adhere a patch over the inferior surface. Typically, this is done in order to prevent a crack from initiating, or to prevent an already existing crack from growing. Evaluation of the efficiency of the patch has traditionally been done with respect to the extent of crack growth, (e.g. Park et al. 1992, and Paul and Jones, 1992), which of course is of crucial interest. However, the integrity of the patched system needs to be considered as well, since the failure of the composite system (formed by the patch and the base structure) may lead to a rapid growth of the preexisting crack in the base structure and may have overall catastrophic consequences. In this study we are therefore interested in investigating the initiation of debonding between the patch and the base structure, as well as the extent and stability of the debonding. Early studies we conducted with respect to debonding suggested that relative long and relative compliant patches were preferred. Furthermore, an investigation regarding the effects of edge tapering on the debonding behavior showed that there are situations where a beveled edge may increase the propensity for debonding, requiring careful selection to achieve a suitable taper angle. In the present study, we investigate the integrity of the composite system for a base structure made from aluminum, and the patch made from aluminum or fiber reinforced epoxy, where both carbon and glass fiber are studied. In particular, we compare the materials selection in the patch, and for the case of a fiber-reinforced epoxy we also discuss the lay-up sequence. To model the debonding behavior, an analytical model developed previous is extended to allow for the current materials properties. This model is fully self consistent and includes a Griffith type fracture criteria which yields the condition for the propagating bond zone boundary. The model also considers the unbonded part of the patch, which has earlier been shown to be in either of three configurations: (i) full sliding contact between the unbonded part of the patch and the base structure, (ii) only the edge of the patch remains in sliding contact with the base structure, or (iii) the patch has totally lifted of the base structure. Results for both flat and curved structures are presented, as well as for a range of loading and boundary conditions. Among other results, it is seen that the degree of tapering is a more important parameter than the stacking sequence is with respect to the initiation and extent of debonding. Furthermore, a simplified testing method is discussed. In this method, the critical load for a case of simple boundary and loading conditions for a particular material system can be directly translated to the critical load for a more complicated structure.

Bondability and Strength Evaluation of Gold Ball Bond Using Nanoindentation Approach

2016 ◽  
Vol 700 ◽  
pp. 132-141
Author(s):  
Muhammad Nubli Zulkifli ◽  
Azman Jalar ◽  
Shahrum Abdullah ◽  
Norinsan Kamil Othman
Keyword(s):  
Wire Bonding ◽  
Strength Distribution ◽  
Nanoindentation Test ◽  
Ball Bond ◽  
New Approach ◽  
Bonding Parameter ◽  
Responsible Mechanism ◽  
Reduced Modulus ◽  
Gold Ball ◽  
Ball Bonds

The evaluation of the strength and bondability of gold, Au ball bond requires a new approach to provide a more detail data. Nanoindentation test was used as a new approach to evaluate the strength distribution and bondability of Au ball. Au ball bonds that experienced different value of wire bonding parameter namely bonding force, bonding time, bonding power, and stage temperature were used as samples for the present analysis. The distribution of strength based on hardness and reduced modulus values located at the bonding area of Au ball bonds were found to be related with the values of the wire bonding parameter. Nanoindentation test was found to be a suitable approach to analyze and evaluate the bondability of Au ball bond in a localized and detailed manner. In addition, the responsible mechanism for the thermosonic Au wire bonding can be identified and analyzed by using the results obtained from the nanoindentation test.

Thermal Expansion Behavior of the Multiphase Composite System

2004 ◽  
Vol 449-452 ◽  
pp. 765-768
Author(s):  
Chong Sung Park ◽  
Hyun Seok Hong ◽  
Myung Ho Kim ◽  
Chong Mu Lee
Keyword(s):  
Thermal Expansion ◽  
Composite System ◽  
Welding Process ◽  
High Volume ◽  
Volume Percent ◽  
New Approach ◽  
Composite Systems ◽  
Expansion Behavior ◽  
The Matrix ◽  
Multiphase Composite

A new approach for the CTE on the basis of Ashelby.s cutting and welding process was made for the analysis of the thermal expansion behaviors of Al-Si alloys and composites. In this theoretical approach, it was considered that relaxation of residual stress could create an elastoplastic zone in the matrix around a particle during cooling. A comparison of the measured CTEs with the calculated ones for the Al-Si-SiCp and Al-Si-Al2O3 composite systems was performed in terms of the volume percent and the size of reinforced phases. The calculated results revealed that the linear CTE of the both composite depends on the size of the reinforce phases, especially at the composite systems with a low volume percent of the reinforce phases. The increase in the volume percentages of Al2O3, SiCp and Si phase lowers the linear CTEs of the systems. The measured CTEs was deviated less than about ten percents from the calculated ones at composites with a high volume percent. The deviations of the CTEs of reinforced phases are about 4 - 6 vol% from real composite systems.

Failure Analysis of CCF300/5428 Laminates under Low Velocity Impact Based on Properties of Advanced Composite Material

2013 ◽  
Vol 387 ◽  
pp. 185-188
Author(s):  
Jian Yu Zhang ◽  
Ming Li ◽  
Li Bin Zhao ◽  
Bin Jun Fei
Keyword(s):  
Failure Analysis ◽  
Composite Laminates ◽  
Damage Model ◽  
Failure Criteria ◽  
Low Velocity Impact ◽  
Material System ◽  
Low Velocity ◽  
3D Fem ◽  
Velocity Impact ◽  
The Impact

A progressive damage model (PDM) composed by 3D FEM, Hashin and Ye failure criteria and Changs degradation rules was established to deeply understand the failure of a new material system CCF300/5428 under low velocity impact. User defined subroutines were developed and embedded into the general FEA software package to carry out the failure analysis. Numerical simulations provide more information about the failure of composite laminates under low velocity impact, including initial damage status, damage propagation and final failure status. The history of the impact point displacement and various damage patterns were detailed studied.

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