Wyniki wyszukiwania - Biblioteka Nauki

1

Failure Analysis of Thin-Walled Composite Profile Subjected to Axial Compression

100%

Różyło P.

Advances in Science and Technology. Research Journal

|

2019

|

tom Vol. 13, no 3

170--178

EN

The paper describes a numerical and experimental study investigating the load carrying capacity of thin-walled composite structure subjected to axial compression. Composite profile was made of carbon-epoxy laminate with symmetrical arrangement of the layers [90/-45/45/0]s. The experiment was performed on a universal testing machine (Zwick Z100) until total failure of the column. In case of experimental study, post-critical equilibrium paths in full range of loads of the structure were determined. The numerical analysis was performed by the finite element method using the Abaqus® software. Numerical analysis involved solving a nonlinear stability problem. The geometrically non-linear problem was solved by the Newton-Raphson method. The load carrying capacity of the composite structure was determined by the progressive failure analysis, which firstly estimates damage initiation load (Hashin criterion) and secondly estimates failure load (energy criterion). The numerical and experimental results show high agreement, which confirms the adequacy of the prepared numerical model of composite profile.

2

A study of failure analysis of composite profile with open cross-section under axial compression

84%

Różyło P.

Composites Theory and Practice

|

2018

|

tom R. 18, nr 4

210--216

EN

The paper presents an experimental and numerical study investigating the load carrying capacity of thin-walled composite structures with an omega-shaped cross-section subjected to axial compression. The tested profile was made of carbon-epoxy laminate with symmetrical arrangement of the layers [0/90/0/90]s. The experimental tests were performed on a universal testing machine - Zwick Z100, under full load conditions until total failure of the structure. The post-critical equilibrium paths of the construction were determined, defining the relationship between compressive load and deflection and enabling the FE models to be validated. Based on the obtained post-critical equilibrium paths, the critical load of the construction was determined using well-known approximation methods. Simultaneously, numerical analysis was carried out by the finite element method using Abaqus® software. The critical state was determined via linear eigenvalue analysis, and the critical load and corresponding first buckling mode were estimated. The next stage of numerical analysis involved solving the nonlinear stability problem of the structure with initialized geometric imperfection reflecting the first buckling mode of the composite material. The geometrically non-linear problem was solved by the Newton-Raphson method. The load capacity of the composite profile in the post-buckling state was determined by the progressive failure criterion which estimates damage initiation in the composite material using the Hashin criterion. Progressive failure analysis is described with the energy criterion describing the stiffness degradation of finite elements. The obtained numerical simulation results showed very high correspondence with the presented experimental results conducted on real structures, which confirms the precise preparation of the developed numerical models of the composite structures.

PL

Praca dotyczy numeryczno-doświadczalnego badania nośności cienkościennych struktur kompozytowych o omegowym kształcie przekroju poprzecznego poddanych osiowemu ściskaniu. Profile wykonano z kompozytu węglowo-epoksydowego o symetrycznym układzie warstw względem płaszczyzny środkowej. W ramach przeprowadzonych badań rozpatrzono układ o krzyżowej konfiguracji ułożenia warstw laminatu [0/90/0/90]s. Badania eksperymentalne przeprowadzono z wykorzystaniem uniwersalnej maszyny wytrzymałościowej Zwick Z100 w pełnym zakresie obciążeń, aż do całkowitego zniszczenia konstrukcji. Badania numeryczne stanu krytycznego z zastosowaniem liniowej analizy zagadnienia własnego miały na celu wyznaczenie postaci wyboczenia oraz wartości obciążenia krytycznego. Kolejny etap symulacji numerycznych obejmował rozwiązanie zagadnienia nieliniowej stateczności konstrukcji z zainicjowaną najniższą postacią wyboczenia. Zagadnienie geometrycznie nieliniowe prowadzono z wykorzystaniem przyrostowo-iteracyjnej procedury Newtona-Raphsona, wykorzystując jako narzędzie do obliczeń numerycznych program ABAQUS® . Obliczenia numeryczne utraty nośności konstrukcji przeprowadzono za pomocą implementacji algorytmu progresywnego kryterium zniszczenia (uwzględniając degradację sztywności elementów skończonych), w oparciu o uprzednio uwzględnione inicjacyjne kryterium zniszczenia Hashina. Otrzymane wyniki symulacji numerycznych wykazywały bardzo wysoką zgodność z prezentowanymi wynikami badań eksperymentalnych, prowadzonych na rzeczywistych strukturach. Wysoka zbieżność wyników świadczy o precyzyjnym przygotowaniu modelu MES.

3

Stability and failure of thin-walled composite structures with a square cross-section

84%

Czajka B. , Różyło P. , Dębski H.

|

2022

|

tom Vol. 18, no 2

43--55

EN

This paper is devoted to the analysis of the stability and load-carrying capacity of thin-walled composite profiles in compression. The specimens reflect elements made of carbon fibre reinforced laminate (CFRP). Thin-walled columns with a square cross-section were made from 4 layers of composite in 3 different combinations of layer arrangements. Advanced numerical analyses have been carried out. In the first stage of the study, a buckling analysis of the structure was performed. In further numerical simulations, two advanced models were used simultaneously: the Progressive Failure Analysis (PFA) and the Cohesive Zone Model (CZM). The results showed significant differences between the critical load values for each layer configuration. The forms of buckling and the areas of damage initiation and evolution were also dependent on the applied layup.

4

Determination and verification of mechanical properties of gfrp filament wound pipes

67%

Krzysztoporski M. , Paczkowska K. , Pacholec Z. , Błażejewski W.

Composites Theory and Practice

|

2024

|

tom R. 24, nr 3

188--193

EN

Filament winding is an efficient and versatile manufacturing technique utilised to create lightweight high-strength composite structures. Glass fiber reinforced polymers (GFRP) are widely used in filament winding and can be characterised by high tensile strength, corrosion resistance, and favourable stiffness-to-weight ratios. These properties make GFRP composites suitable for various industries such as aerospace, automotive, marine, and civil engineering. Despite their widespread use, accurately identifying and verifying the mechanical properties of GFRP filament wound structures presents significant challenges. This study addresses these challenges by presenting methods to ascertain and verify the mechanical properties of GFRP filament wound pipes. Commercial pipes from Plaston-P composed of an inner PVC layer and an outer shell of glass fiber roving and mat impregnated with polyester resin were examined. Various mechanical tests were conducted, including tensile, compression, and shear tests, following ASTM standards. This paper describes the steps taken to prepare the specimens required for those tests with a strong focus on reproducing the most representative structure, highlighting potential inaccuracies in parameter identification. Finite element (FE) simulations were performed to verify the obtained parameters, using a nonlinear orthotropic material model with a progressive failure approach. The results showed that the simulated value of the apparent tensile strength of the specimen is 75.94 MPa. The fracture of the element was initiated by failure of the roving- resin layers, which was sudden and brittle. The simulation results were compared with the experimental data obtained from split disk tests according to ASTM D2290. The average apparent tensile stress from the experiment was 80.65 MPa and the specimens failed in a brittle manner. The comparison showed a satisfactory correlation between the simulation and the experiment with a value difference of approximately 6 %. The failure mechanism was also identical. It proves that the adopted method of identification allows the mechanical properties to be characterised correctly. Future research will focus on improving the correlation between the simulation and experiment by incorporating parameters to account for delamination and continuous damage of the composite.