Experimental and Numerical Measurement of the Impact Strength of Poly-lactic Acid through a Low-velocity Impact

Poly Lactic Acid (PLA) is a biodegradable material which is being extensively used in industrial applications. Due to its low glass transition temperature and cost, PLA is ideal as a feed stock in 3D printing applications. However, it has a brittle nature which makes it vulnerable to impact loads. In this paper, PLA is used to make 3D printed plates that are impact tested using an in-house low velocity impact test apparatus. A high-speed camera and an infrared thermography system are used to investigate the impact damage properties of the material. The plates manufactured with 0° orientation are used to conduct two different experiments; one with varying energies and the other with varying thickness at two different impact locations, namely at plate’s centre and close to a clamped edge. At 1 J impact energy, the plates showed a tensile crack behaviour (cracks between extrudates) and for 3 J energy it showed a mixed crack behaviour of tensile and shear (cracks along and across extrudates) with more energy dissipations than the 1 J impact. For the 1 J impact, more energy is dissipated at the centre of the plate (42.3%) than the impact close to a clamped edge (32.8%), whereas for the 3 J impact more energy is dissipated near clamped edges (97.1%) compared to the centre of the plate (54.9%). Subsequently, the 3 J impact is used for the second experiment due to the higher energy dissipation. Finally, an experimental study is conducted on plates with varied layer thickness from 0.10 mm to 0.18 mm. Results show that the increase in layer thickness (decrease in number of layers) increases the impact absorption for plates impacted at their centre. For plates impacted near their clamped edge, a zig-zag impact damage pattern of increasing and decreasing magnitudes is observed, but the energy dissipation values are higher than the centre impacted plates.

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Extperimental Characterization of 3D Printed Thermoplastic Plates Subjected To Low Velocity Impact

10.32920/ryerson.14654682.v1 ◽

2021 ◽

Author(s):

Hari Prasad Prudhvi Desu

Keyword(s):

Energy Dissipation ◽

Layer Thickness ◽

Impact Damage ◽

Low Velocity Impact ◽

Poly Lactic Acid ◽

Low Velocity ◽

Velocity Impact ◽

3D Printed ◽

The Impact ◽

Clamped Edge

Poly Lactic Acid (PLA) is a biodegradable material which is being extensively used in industrial applications. Due to its low glass transition temperature and cost, PLA is ideal as a feed stock in 3D printing applications. However, it has a brittle nature which makes it vulnerable to impact loads. In this paper, PLA is used to make 3D printed plates that are impact tested using an in-house low velocity impact test apparatus. A high-speed camera and an infrared thermography system are used to investigate the impact damage properties of the material. The plates manufactured with 0° orientation are used to conduct two different experiments; one with varying energies and the other with varying thickness at two different impact locations, namely at plate’s centre and close to a clamped edge. At 1 J impact energy, the plates showed a tensile crack behaviour (cracks between extrudates) and for 3 J energy it showed a mixed crack behaviour of tensile and shear (cracks along and across extrudates) with more energy dissipations than the 1 J impact. For the 1 J impact, more energy is dissipated at the centre of the plate (42.3%) than the impact close to a clamped edge (32.8%), whereas for the 3 J impact more energy is dissipated near clamped edges (97.1%) compared to the centre of the plate (54.9%). Subsequently, the 3 J impact is used for the second experiment due to the higher energy dissipation. Finally, an experimental study is conducted on plates with varied layer thickness from 0.10 mm to 0.18 mm. Results show that the increase in layer thickness (decrease in number of layers) increases the impact absorption for plates impacted at their centre. For plates impacted near their clamped edge, a zig-zag impact damage pattern of increasing and decreasing magnitudes is observed, but the energy dissipation values are higher than the centre impacted plates.

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Response and failure modes of biaxial warp-knitted flexible composite subject to low-velocity impact

Journal of Industrial Textiles ◽

10.1177/15280837211015477 ◽

2021 ◽

pp. 152808372110154

Author(s):

Ziyu Zhao ◽

Tianming Liu ◽

Pibo Ma

Keyword(s):

Impact Energy ◽

Linear Density ◽

Failure Modes ◽

Impact Response ◽

Low Velocity Impact ◽

Minor Effect ◽

Low Velocity ◽

Velocity Impact ◽

Flexible Composites ◽

The Impact

In this paper, biaxial warp-knitted fabrics were produced with different high tenacity polyester linear density and inserted yarns density. The low-velocity impact property of flexible composites made of polyurethane as matrix and biaxial warp-knitted fabric as reinforcement has been investigated. The effect of impactor shape and initial impact energy on the impact response of flexible composite is tested. The results show that the initial impact energy have minor effect on the impact response of the biaxial warp-knitted flexible composites. The impact resistance of flexible composite specimen increases with the increase of high tenacity polyester linear density and inserted yarns density. The damage morphology of flexible composite materials is completely different under different impactor shapes. The findings have theoretical and practical significance for the applications of biaxial warp-knitted flexible composite.

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Coda Waves for Health Monitoring of Composites Under Low-Velocity Impact

10.1115/qnde2021-75297 ◽

2021 ◽

Author(s):

Subal Sharma ◽

Vinay Dayal

Keyword(s):

Ultrasonic Waves ◽

Coda Waves ◽

Low Velocity Impact ◽

Coda Wave ◽

Low Velocity ◽

Fibrous Composite Material ◽

Velocity Impact ◽

Isotropic Composite ◽

The Impact ◽

Impact Damages

Abstract Coda waves have been shown to be sensitive to lab-controlled defects such as very small holes in fibrous composite material. In the real world, damages are subtler and more irregular. The main objective of this work is to investigate coda wave capability to detect low-velocity impact damages. The emphasis is to detect the presence of barely visible impact damages using ultrasonic waves. Detection of incipient damage state is important as it will grow over the life of the structure. Differential features, previously used in similar work, have been utilized to detect realistic impact damages on carbon fiber composites. Quasi-isotropic composite laminates were subjected to low-velocity impact energy ranging from 2J to 4.5J. Two differential features reported could be used detect the presence of damage. It is also observed that ply orientation can be a deterministic factor for indicating damages. The size and shape of the impact damage has been characterized using ultrasonic C-scans. Results indicate that coda waves can be used for the detection of damage due to low-velocity impact.

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Low Velocity and Compression-After-Impact Response of Pin-Reinforced Sandwich Composites

10.1115/imece1999-0499 ◽

1999 ◽

Author(s):

Uday K. Vaidya ◽

Mohan V. Kamath ◽

Mahesh V. Hosur ◽

Anwarul Haque ◽

Shaik Jeelani

Keyword(s):

Impact Testing ◽

Low Velocity Impact ◽

Sandwich Composites ◽

Low Velocity ◽

Static Compression ◽

Velocity Impact ◽

Transverse Stiffness ◽

Impact Studies ◽

Compression After Impact ◽

The Impact

Abstract In the current work, sandwich composite structures with innovative constructions referred to as Z-pins, or truss core pins are investigated, in conjunction with traditional honeycomb and foam core sandwich constructions, such that they exhibit enhanced transverse stiffness, high damage resistance and furthermore, damage tolerance to impact. While the investigations pertaining to low velocity impact have appeared recently in Vaidya et al. 1999, the current paper deals with compression-after-impact studies conducted to evaluate the residual properties of sandwich composites “with” and “without” reinforced foam cores. The resulting sandwich composites have been investigated for their low velocity (< 5 m/sec) impact loading response using instrumented impact testing at energy levels ranging from 5 J to 50 J impact energy. The transverse stiffness of the cores and their composites has also been evaluated through static compression studies. Compression-after-impact studies were then performed on the sandwich composites with traditional and pin-reinforcement cores. Supporting vibration studies have been conducted to assess the changes in stiffness of the samples as a result of the impact damage. The focus of this paper is on the compression-after-impact (CAI) response and vibration studies with accompanying discussion pertaining to the low velocity impact.

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Effect of SiO2 Nanoparticles on the Mechanical and Low Velocity Impact Properties of Epoxy/Glass Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.838.29 ◽

2016 ◽

Vol 838 ◽

pp. 29-35

Author(s):

Michał Landowski ◽

Krystyna Imielińska

Keyword(s):

Flexural Strength ◽

Energy Absorption ◽

Impact Energy ◽

Epoxy Matrix ◽

Low Velocity Impact ◽

Low Velocity ◽

Nanoparticle Suspension ◽

Impact Properties ◽

Velocity Impact ◽

The Impact

Flexural strength and low velocity impact properties were investigated in terms of possibile improvements due to epoxy matrix modification by SiO2 nanoparticles (1%, 2%, 3%, 5%, 7%wt.) in glass/epoxy laminates formed using hand lay-up method. The matrix resin was Hexion L285 (DGEBA) with Nanopox A410 - SiO2 (20 nm) nanoparticle suspension in the base epoxy resin (DGEBA) supplied by Evonic. Modification of epoxy matrix by variable concentrations of nanoSiO2 does not offer significant improvements in the flexural strength σg, Young’s modulus E and interlaminar shear strength for 1% 3% and 5% nanoSiO2 and for 7% a slight drop (up to ca. 15-20%) was found. Low energy (1J) impact resistance of nanocomposites represented by peak load in dynamic impact characteristics was not changed for nanocompoosites compared to the unmodified material. However at higher impact energy (3J) nanoparticles appear to slightly improve the impact energy absorption for 3% and 5%. The absence or minor improvements in the mechanical behaviour of nanocomposites is due to the failure mechanisms associated with hand layup fabrication technique: (i.e. rapid crack propagation across the extensive resin pockets and numerous pores and voids) which dominate the nanoparticle-dependent crack energy absorption mechanisms (microvoids formation and deformation).

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Low Velocity Impact on Fiber Reinforced Geocomposites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.827.145 ◽

2016 ◽

Vol 827 ◽

pp. 145-148 ◽

Cited By ~ 4

Author(s):

Sneha Samal ◽

David Reichmann ◽

Iva Petrikova ◽

Bohdana Marvalova

Keyword(s):

Impact Damage ◽

Acoustic Vibration ◽

Low Velocity Impact ◽

Low Velocity ◽

Velocity Impact ◽

Impact Behaviour ◽

Reinforced Composite ◽

Before And After ◽

Two Parameters ◽

The Impact

Low velocity impact strength of the fabric reinforced geocomposite has investigated in this article. Various fabrics such as carbon and E-glass were considered for reinforcement in geopolymer matrix. The primary two parameters such as low velocity, impact damage modes are explained on the E-glass and carbon based fabric geocomposite. The onset mode of damage to failure mode is examined through C-scan analysis. The quality of the composite is observed using c-scan with acoustic vibration mode of sensor before and after impact test. Then the effect of fabric and matrix on the impact behaviour is discussed. Residual strength of the composite is measured to determine post impact behaviour. It has been observed that resistance properties of E-glass reinforced composite is better than carbon fabric reinforced composite.

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