Strain-rate-dependent failure criteria for composites

This paper deals with the problem of stress distribution in orthotropic and laminated plates subjected to central concentrated load. An equivalent single layer trigonometric shear deformation theory taking into account transverse shear deformation effect as well as transverse normal strain effect is used to obtain in-plane normal and transverse shear stresses through the thickness of plate. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. A simply supported plate with central concentrated load is considered for the numerical analysis. Anomalous behavior of inplane normal and transverse shear stresses is observed due to effect of stress concentration compared to classical plate theory and first order shear deformation theory.

In order to study the dynamic compression mechanical properties of engineering rock under high strain rate （100~102 S−1）loads, dynamic compression tests of three common engineering rocks (marble, sandstone and granite) taken from the Qinling Mountain are studied subjected to five different kinds of shock air pressure using Φ 100 mm split Hopkinson pressure bar test system improved with purple copper waveform shaper. The dynamic compression stress-strain curves, dynamic compressive strength, peak strain, energy absorption rate and elastic modulus of three rocks variation with strain rate are researched. The dynamic compression failure modes under different strain rates are analyzed. Then the three-dimensional numerical simulations of waveform shaper shaping effects and stress wave propagation in the SHPB tests are carried out to reproduce the test results. The research results show that the dynamic compression stress-strain curves show certain discreteness, and there is an obvious rebound phenomenon after the peak. With the increase in strain rate, the dynamic compressive strength, peak strain and energy absorption rate are all in a certain degree of increase, but the elastic modulus have no obvious change trend. Under the same strain rate, the dynamic compressive strength of granite is greatest while of sandstone is least. With the increase in strain rate, the margin of increase in peak strain and energy absorption rate of granite is greatest while of sandstone is least. The failure modes of the sample experience a developing process from outside to inside with the increase of strain rate.

Strain rate effect on in-plane shear strength of unidirectional polymeric composites

Interface tensile and fracture behavior of the Ti/Al3Ti Metal-Intermetallic Laminate (MIL) composite under quasi-static and high strain rates

Efficient linear transverse normal stress analysis of layered composite plates

Hot tensile tests were carried out to investigate hot ductility behavior and critical temperature range (ΔT) between zero strength temperature (ZST) and zero ductility temperature (ZDT) of tool steel grades AISI L3 and O1. The test specimens solidified from melting at cooling rate of 0.5℃/s and 3℃/s to the test temperature in the range between liquidus and 900℃. The specimens were then strained to failure at strain rate of 2x10⁻³/s and 2x10⁻²/s. Quenching test was carried out in order to investigate the microstructure occurred during hot tensile test. The microstructure that appeared in quenched specimen was then identified with SEM-EDX. It was found that the critical temperature range of the steels solidified at the slow or the fast cooling rate, widened with increasing strain rate. The specimens which solidified at slow cooling rate when tensile strained to failure at low or high strain rate, had wider critical temperature range than the specimens that solidified at fast cooling rate. For steel grade AISI L3, tensile test at high and low strain rate (after solidified at the fast cooling rate) revealed the hot ductility of 35-65%RA between 900-1250℃. Whereas, the hot ductility of the samples which solidified at slow cooling rate and pulled at slow strain rate were markedly higher than those pulled at higher strain rate between 900-1200℃. Precipitation of manganese sulfide in the interdendritic region resulted in deterioration of hot ductility of steel grade AISI L3. For steel grade AISI O1, tensile tests of specimens solidified between 900-1100℃ at slow cooling rate and low strain rate yielded higher hot ductility than those specimens pulled at high strain rate. The hot ductility of samples at fast cooling rate and low strain rate showed no difference to those samples of hot tested at high strain rate. Nevertheless, slow cooling rate affected hot ductility more than fast cooling rate for tensile tests at both high and low strain rate. Carbide precipitates of vanadium, tungsten and chromium along austenite grain boundaries influenced the ductility loss of steel grade AISI O1.

Three-dimensional characterization of textile composites

The effects of loading-direction and strain-rate on the mechanical behaviors of human frontal skull bone

Analytical zigzag formulation with 3D elasticity corrections for bending and stress analysis of circular/annular composite sandwich plates with auxetic cores

Axiomatic/asymptotic PVD/RMVT-based shell theories for free vibrations of anisotropic shells using an advanced Ritz formulation and accurate curvature descriptions

The northeastern part of India, characterized by numerous fault zones, is responsible for varied seismic activity, including large, moderate, and small earthquakes. The current study examines strain rate variations in the region to provide insights into its tectonic deformation and seismic hazard potential. The analysis of strain rates derived from the GPS velocity field reveals a complex deformation pattern, encompassing distinct zones of extensional, compressional, and shear deformation. The dilatation strain rate map highlights regions of positive and negative dilation, corresponding to extensional and compressional deformation, respectively, and indicative of normal and thrust faulting environments. The shear strain map identifies zones with high shear strain rates, marking areas prone to strike-slip faulting. High strain rates are observed along major fault zones, such as the Kopili, Dhubri, and Bomdila faults, as well as the Indo-Burma subduction zone. These findings highlight areas of significant deformation and high seismic risk. The Kopili Fault Zone, in particular, exhibits high compressional strain rates, suggesting a likelihood of future ruptures. The occurrence of the M6.4 earthquake in 2021 near the Kopili Fault, with a combination of thrust and strike-slip faulting, supports our hypothesis. Similarly, the high shear strain rates along major fault zones, such as the Dhubri and Bomdila faults, indicate these areas as potential sites for future significant earthquakes with strike-slip faulting mechanism. We recommend continuous monitoring of strain rate variation to enable a more accurate assessment of seismic hazard in the region.

Dynamic uniaxial and biaxial stress-strain relationships for austenitic stainless steels

Analytical solution for bending and buckling analysis of functionally graded plates using inverse trigonometric shear deformation theory

Through-the-thickness stress distributions near edges of composite laminates using stress recovery scheme and third order shear and normal deformable theory

On mechanical behavior of two-layer functionally graded sandwich curved beams resting on elastic foundations using an analytical solution and refined Timoshenko beam theory