**2.1 Material**

The materials used in this study are matrix polymeric (PPS, polyphenylene sulfide) fiber-reinforced composites, which were selected due to their application on aircraft structures such as leading edges, door structures, and pylon engine covers, among others [32–36]. These materials were provided by TenCate in the form of rectangular laminates in two versions:

a.33-ply-thick laminate consisting of carbon fabric, 5HS style (harness-satin weave where one filling yarn floats over four warp yarns and under one, **Figure 1a**), 3K (3000 individual strands of carbon per fiber bundle) T300J (Toray Carbon Fibers America, Inc. specification, commonly used in aerospace applications), and 280 gsm FAW (fiber area weight in grams per square meter), combined with 42% RC (resin content by weight) Fortron 214 PPS in an orthotropic (0, 90) balanced/mirrored layup (**Figure 1a**)

**31**

**Figure 2.**

*Isometric view of the specimen.*

*High Strain Rate Characterization of Thermoplastic Fiber-Reinforced Composites…*

orthotropic (0, 90) balanced/mirrored layup (**Figure 1b**).

b.42-ply-thick laminate consisting of fiberglass fabric, 8HS style (harnesssatin weave where one filling yarn floats over seven warp yarns and under one, **Figure 1b**), EC6 yarn (e-glass continuous fiber with filament diameter of 6 μm), and 300 gsm FAW (fiber area weight in grams per square meter), combined with 33% RC (resin content by weight) Fortron 214 PPS in an

from the originals bars using the Extec Labcut 5000, available on the Lightweight Structures Laboratory of the Instituto de Pesquisas Tecnológicas (IPT), which guarantees samples with parallel tolerance of 0.03 mm. The geometry of the specimens was set between the ranges specified to accomplish with the assumptions made about inertia and friction effect [28]. **Figure 2** shows the specimen configuration;

Quasi-static reference tests were performed at the Lightweight Structures Laboratory (IPT), using an INSTRON servo-mechanic universal testing machine at three constant displacement rates (0.6, 6, and 60 mm/min), which corresponds to three quasi-static

10 mm. Load measurements were recorded using universal testing machine hardware and software, while an Imetrum video gauge system synchronized with the testing machine was used to measure strain in the specimen. Using the software interface, target points were placed at the center of the specimen, and the strain measurements were recorded during the test; additional targets were set to monitor strain behavior.

Special testing fixtures, with load distribution system, were used in the testing machine movable head member in order to ensure alignment during specimen load-

Longitudinal compressive strength is calculated, for this regimen, according to expression σ\_S = P/AS, where P is the applied load recorded by universal testing machine hardware and software and AS is the cross-sectional area of the specimen [38]. Strength and strain data are post-processed to build up the stress-strain curves for quasi-static regime and to calculate peak stress, strain at peak stress, and Young's modulus in order to compare mechanical properties with those obtained in the dynamic regime. Experimental Young's modulus is determined as the slope of the linear regression (LR) applied to the stress-strain curve in the range of strain data

ing process. **Figure 3** represents a schematic setup for quasi-static tests.

(width × length × height) were cut

by considering the nominal specimen length of

*DOI: http://dx.doi.org/10.5772/intechopen.82215*

Rectangular specimens of 9 × 10 × 9.8 mm3

red arrows indicate the load direction.

axial strain rates 0.001, 0.01, and 0.1 s<sup>−</sup><sup>1</sup>

**2.2 Quasi-static test**

between 0.7 and 1%.

**Figure 1.** *Harness-satin weave (a) 5HS and (b) 8HS [37].*

*High Strain Rate Characterization of Thermoplastic Fiber-Reinforced Composites… DOI: http://dx.doi.org/10.5772/intechopen.82215*

b.42-ply-thick laminate consisting of fiberglass fabric, 8HS style (harnesssatin weave where one filling yarn floats over seven warp yarns and under one, **Figure 1b**), EC6 yarn (e-glass continuous fiber with filament diameter of 6 μm), and 300 gsm FAW (fiber area weight in grams per square meter), combined with 33% RC (resin content by weight) Fortron 214 PPS in an orthotropic (0, 90) balanced/mirrored layup (**Figure 1b**).

Rectangular specimens of 9 × 10 × 9.8 mm3 (width × length × height) were cut from the originals bars using the Extec Labcut 5000, available on the Lightweight Structures Laboratory of the Instituto de Pesquisas Tecnológicas (IPT), which guarantees samples with parallel tolerance of 0.03 mm. The geometry of the specimens was set between the ranges specified to accomplish with the assumptions made about inertia and friction effect [28]. **Figure 2** shows the specimen configuration; red arrows indicate the load direction.

#### **2.2 Quasi-static test**

*Aerospace Engineering*

**2. Methodology**

rectangular laminates in two versions:

*Harness-satin weave (a) 5HS and (b) 8HS [37].*

**2.1 Material**

and carbon fibers [3, 5, 7–13]. The few works found in open literature about thermoplastic composites studied polyamide-reinforced composites (with glass and carbon fiber with different fiber configurations), ethylene-propylene copolymer (EPC) matrix reinforced with discontinuous glass fibers, commingled e-glass/polypropylene woven fabric composite, glass fiber-reinforced polypropylene (PP) and polybutene-1 (PB-1), and AS4 graphite/polyetheretherketone (PEEK) thermoplastic composite [4, 11, 14–20]; however there is a lack of information about PPS matrix composite's behavior. Among the several techniques to achieve high strain rates for tests [21], the split-Hopkinson pressure bar testing is often used for composite materials [3, 5, 10, 18, 22–29], where both the specimen stress-time and the specimen strain-time response are calculated from the strain waves measured on the bars. Additionally, high-speed camera technology with high resolution allow to apply optical and contactless strain field measurement techniques such as digital image correlation (DIC), to obtain accurate data reduction possibilities and more information on the distribution of strain over the specimen surface, which will be later employed in the dynamic material characterization [11, 26, 30, 31]. Within this context, the present work uses these techniques to characterize the strain rate effects on the mechanical behavior of PPS matrix carbon fiber-reinforced composite under compressive loadings in both static and dynamic regimes. Results obtained from dynamic statics are compared with quasi-static test results for the same specimen geometry and batch. Images obtained by high-speed imaging are used during tests to help to identify macro-failure modes induced at high strain rate tests, while micro-failure observation was carried out to identify quasi-static

failure aspects and damage mechanisms of the material at all tested strain rates.

The materials used in this study are matrix polymeric (PPS, polyphenylene sulfide) fiber-reinforced composites, which were selected due to their application on aircraft structures such as leading edges, door structures, and pylon engine covers, among others [32–36]. These materials were provided by TenCate in the form of

a.33-ply-thick laminate consisting of carbon fabric, 5HS style (harness-satin weave where one filling yarn floats over four warp yarns and under one, **Figure 1a**), 3K (3000 individual strands of carbon per fiber bundle) T300J (Toray Carbon Fibers America, Inc. specification, commonly used in aerospace applications), and 280 gsm FAW (fiber area weight in grams per square meter), combined with 42% RC (resin content by weight) Fortron 214 PPS in an

orthotropic (0, 90) balanced/mirrored layup (**Figure 1a**)

**30**

**Figure 1.**

Quasi-static reference tests were performed at the Lightweight Structures Laboratory (IPT), using an INSTRON servo-mechanic universal testing machine at three constant displacement rates (0.6, 6, and 60 mm/min), which corresponds to three quasi-static axial strain rates 0.001, 0.01, and 0.1 s<sup>−</sup><sup>1</sup> by considering the nominal specimen length of 10 mm. Load measurements were recorded using universal testing machine hardware and software, while an Imetrum video gauge system synchronized with the testing machine was used to measure strain in the specimen. Using the software interface, target points were placed at the center of the specimen, and the strain measurements were recorded during the test; additional targets were set to monitor strain behavior.

Special testing fixtures, with load distribution system, were used in the testing machine movable head member in order to ensure alignment during specimen loading process. **Figure 3** represents a schematic setup for quasi-static tests.

Longitudinal compressive strength is calculated, for this regimen, according to expression σ\_S = P/AS, where P is the applied load recorded by universal testing machine hardware and software and AS is the cross-sectional area of the specimen [38].

Strength and strain data are post-processed to build up the stress-strain curves for quasi-static regime and to calculate peak stress, strain at peak stress, and Young's modulus in order to compare mechanical properties with those obtained in the dynamic regime. Experimental Young's modulus is determined as the slope of the linear regression (LR) applied to the stress-strain curve in the range of strain data between 0.7 and 1%.

**Figure 2.** *Isometric view of the specimen.*

**Figure 3.** *Quasi-static compression test setup.*
