Measurement of low velocity and quasi‐static failure modes in PMMA

Abstract

An investigation of the low velocity impact and quasi‐static failure of polymethylmethacrylate (PMMA) based on global and local strain measurements was conducted. Local strains were obtained from surface‐mounted fiber Bragg grating (FBG) sensors, and they were combined with global measurements from quasi‐static indentation and low‐velocity impact experiments to obtain detailed maps of how failure evolves. For both loading regimes, the interactions between the host PMMA specimens and the sensors played a crucial role in the evolution of residual strains. A mapping of the strains clearly shows that strains decrease radially, from high values near the point of impact to far‐field values. Sensors located in critical locations had the highest residual strains prior to PMMA fracture. Furthermore, it was determined that strain transfer to the sensor is strongly influenced by the bonding conditions at the specimen's surface. Because of the debonding of the sensor and the frictional effects associated with the bonding agent, compressive residual strains occurred on the rear‐surface. Hence, a detailed understanding of how strain evolves due to sensor–host interactions and catastrophic fracture can be obtained, which can potentially be used to mitigate damage in PMMA for a range of strain rates. POLYM. COMPOS., 28:381–391, 2007. © 2007 Society of Plastics Engineers

Spherically shaped micron-size particle-reinforced PMMA and PC composites for improving energy absorption capability

“…An Instron Dynatup 9250HV drop tower was used for a low-velocity impact test in which the penetrator is driven by gravity [4]. All tested specimens were penetrated by a 6.43 kg impactor that has a 12.7 mm diameter hemispherical tip striker.…”

“…In contrast, typical polymeric materials have different energy absorbing mechanisms, showing either brittle or ductile behavior in such impact loadings; brittle polymers are crushed shattered or cracked [3][4][5], while ductile polymers show high deflection, deep dents, or tear [5][6][7]. Polymers exhibit inferior impact resistance, stiffness, and strength to weight ratio, compared to fibrous composites that are reinforced with fibers or yarns, which play a key role in introducing high impact resistance, and superior mechanical properties into the composite materials.…”

Monitoring and verification of micro‐strain generated inside the laminate subjected to thermal loading through fiber bragg grating sensors and classical laminate theory

“…Although there are numerous studies on the usage of FBG sensors for different purposes in the literature, [10,20,22,29,30] to the best of the authors' knowledge, there is no study on measuring the slight strain variations caused by thermal expansion through FBG sensors by embedding them inside the different layers of a carbon fiber reinforced polymeric laminate and verification of this measured small strain with CLT. This theory is used to predict the residual stresses in carbon fiber-reinforced bismaleimide polymeric composites.…”

Mechanical Behaviors and Thermoforming Features of PMMA Used In-Mold Decoration

“…PMMA is a kind of hard and highly transparent excellent in-mold decoration material, which is very good for thermoforming. Some research on mechanical behaviors of PMMA are discussed in literatures [4][5][6][7][8][9][10][11][12].…”