TY - JOUR

T1 - Influence of a dynamic consolidation force on in situ consolidation quality of thermoplastic composite laminate

AU - Denkena, Berend

AU - Schmidt, Carsten

AU - Kaczemirzk, Maximilian

AU - Schwinn, Max

N1 - Funding Information: Funding: The authors thankfully acknowledge the financial and organizational support of the project Join THIS by the federal state of Lower Saxony and the European Regional Development Fund (ERDF). The publication of this article was funded by the Open Access Fund of the Leibniz Universität Hannover.

PY - 2021/3/22

Y1 - 2021/3/22

N2 - For achieving high quality of in situ consolidation in thermoplastic Automated Fiber Placement, an approach is presented in this research work. The approach deals with the combination of material pre-heating and sub-ultrasonic vibration treatment. Therefore, this research work investigates the influence of frequency dependent consolidation pressure on the consolidation quality. A simplified experimental setup was developed that uses resistance electrical heating instead of the laser to establish the thermal consolidation condition in a universal testing machine. Consolidation experiments with frequencies up to 1 kHz were conducted. The manufactured specimens are examined using laser scanning microscopy to evaluate the bonding interface and differential scanning calorimetry to evaluate the degree of crystallinity. Additionally, the vibration-assisted specimens were compared to specimens manufactured with static consolidation pressure only. As a result of the experimental study, the interlaminar pore fraction and degree of compaction show a positive dependency to higher frequencies. The porosity decreases from 0.60% to 0.13% while the degree of compaction increases from 8.64% to 12.49% when increasing the vibration frequency up to 1 kHz. The differential scanning calorimetry experiments show that the crystallinity of the matrix is not affected by vibration-assisted consolidation.

AB - For achieving high quality of in situ consolidation in thermoplastic Automated Fiber Placement, an approach is presented in this research work. The approach deals with the combination of material pre-heating and sub-ultrasonic vibration treatment. Therefore, this research work investigates the influence of frequency dependent consolidation pressure on the consolidation quality. A simplified experimental setup was developed that uses resistance electrical heating instead of the laser to establish the thermal consolidation condition in a universal testing machine. Consolidation experiments with frequencies up to 1 kHz were conducted. The manufactured specimens are examined using laser scanning microscopy to evaluate the bonding interface and differential scanning calorimetry to evaluate the degree of crystallinity. Additionally, the vibration-assisted specimens were compared to specimens manufactured with static consolidation pressure only. As a result of the experimental study, the interlaminar pore fraction and degree of compaction show a positive dependency to higher frequencies. The porosity decreases from 0.60% to 0.13% while the degree of compaction increases from 8.64% to 12.49% when increasing the vibration frequency up to 1 kHz. The differential scanning calorimetry experiments show that the crystallinity of the matrix is not affected by vibration-assisted consolidation.

KW - AFP

KW - CFRP

KW - In situ consolidation

KW - Thermoplastic

KW - Vibration

UR - http://www.scopus.com/inward/record.url?scp=85104575163&partnerID=8YFLogxK

U2 - 10.3390/jcs5030088

DO - 10.3390/jcs5030088

M3 - Article

AN - SCOPUS:85104575163

VL - 5

JO - Journal of Composites Science

JF - Journal of Composites Science

IS - 3

M1 - 88

ER -