Ageing Module – Basic
The ageing module is recommended when the material operates below the endurance limit. Although cracks may not grow due to mechanical fatigue, the material properties may still evolve with exposure to heat history. The results of this module enable the user to compute fatigue performance considering both unaged and aged material properties.
Experiment Overview:
- ageing in oven at 1 client-specified time and temperature
- static tearing raw data, unaged vs. aged
- cutting force raw data, unaged vs. aged
- number of slabs needed for test: 5
- Recommended for cases with fatigue life longer than 106 cycles, and when ageing must be taken into account for a specific aged condition. Note: It is required to run FPM-IS in order to run this Module.
Ageing Module – Master Curve
The extended life module is recommended when the material operates below the endurance limit. Although cracks may not grow due to mechanical fatigue, the material properties may still evolve with exposure to heat history. A series of oven ageing experiments is used to develop master curves showing the evolution of stiffness, intrinsic strength, and fracture strength with time. The protocol also produces an estimate of the activation energy of the Arrhenius rate law describing the time-temperature dependence of ageing in the material.
Recommended for cases with fatigue life longer than 106 cycles, and when ageing must be taken into account.
Note: It is required to run FPM-IS in order to run this Module.
Experiment Overview
- ageing in oven at 3 temperatures for 3 time periods: 3 days, 10 days, 30 days
- static tearing raw data, 3 ageing periods x 3 ageing temperatures
- cutting force raw data, 3 strain levels x 3 ageing periods x 3 ageing temperatures
- number of slabs needed for test: 30
Creep Crack Growth Model
The creep crack growth rate module produces information useful for cases involving long-term static loads under which time-dependent crack growth (rather than cycle-dependent crack growth) may occur.
Recommended for cases involving long periods under static load
Lab ambient temperature (23°C)
Experiment Overview
- raw data from quasistatic creep crack growth procedure
- number of slabs needed for test: 1
Cycle Softening Module
The cyclic softening module produces information about the rate at which stiffness evolves under cyclic solicitations. This information is useful for modeling stiffness evolution under fatigue cycles using Endurica DT’s stiffness loss cosimulation feature. The experiment is run in displacement control, and it records the evolution of the peak stress with cycles.
Recommended for cases where stiffness degradation limits durability
Experiment Overview
- raw data from cyclic softening procedure on simple tension strips at 5 strain levels
- number of slabs needed for test: 1
Fully Relaxing Module – Required Test
The Core Module gives the basic fatigue crack growth rate curve as well as the strain-life curve and crack precursor size.
This module is a pre-requisite for any fatigue analysis.
Experiment Overview:
- static tearing
- fatigue crack growth (20 hour procedure)
- cyclic simple tension to rupture, 2 strain levels
- number of slabs needed for test: 5
Heat Build-up Analyser
- Characterizes rubber self-heating and thermal runaway properties
- Ideal for calibrating and validating heat build up simulations
- Ideal for calibrating exothermic reaction parameters θx and q̇x for the Endurica thermal runaway model
Imposes dynamic tension/compression strain via bending of a cylindrical specimen that rotates- Controls strain amplitude via the angle of bending, and cycle rate via the rotation speed
- Measures internal and external temperature vs. time
- Easy to use control software
Hyperelastic Module – Required Test
The Hyperelastic Module produces the basic information about nonlinear stress-strain behavior that is needed to run a finite element model and to represent initial transient softening (Mullins effect) in the model.
This module is a pre-requisite for any fatigue analysis.
- simple tension, slow cyclic loading, raw data
- planar tension, slow cyclic loading, raw data
- biaxial tension, slow cyclic loading, raw data
- 5 strain levels
- number of slabs needed for test: 4
Instrumented Chip & Cut Analyser
When there is rolling or sliding contact of a rubber surface over a second hard surface of sufficient roughness, localized cutting and damage of the rubber surface sometimes becomes a problem. It occurs in off-road tires operating on stony surfaces, for example, and it can severely limit the useful life of a tire.
Utilized in the laboratory for:
- Measuring chip and cut resistance of rubber compounds under cyclic impact loadings
- Mimicking conditions experienced in demanding applications – the ICCA is highly instrumented to enable control and measurement of forces and displacements during impact
- Friction and wear measurements when operated in full contact mode
- Highly instrumented to enable control and measurement of forces and displacements during impact to mimic conditions experienced in demanding applications
- The instrument can be also be operated in full contact mode as a friction and wear measurement device
Intrinsic Strength Analyser
- Measures the intrinsic strength of polymers through cutting forces on an instrumented blade of controlled sharpness
- Indicates the threshold fracture mechanical strength of a polymer network (i.e. the mechanical fatigue threshold)
- Based on the Lake and Yeoh procedure (a sufficiently sharp blade can directly load and break molecular bonds without inducing the large viscoelastic process zone and the losses that arise when you drive a crack by ultimate loads or dynamic loads)
- The blade is driven at a very slow, controlled rate into the rubber while all of the forces and displacements involved in the crack tip energy balance are recorded.
- The measurements and data reduction are fully automated and simple to use.
Intrinsic Strength Module
This module measures the material’s intrinsic strength – the minimum energy release rate required to produce crack growth. Operation below this limit does not supply sufficient energy to grow a crack so the intrinsic strength is also called the endurance limit. Use this module when the material is expected to serve for a very large number of cycles.
Required for safety factor/infinite life/fatigue limit analysis .
Recommended for cases with fatigue life longer than 106 cycles.
Experiment Overview
- cutting force vs. strain, minimum 3 strain levels
- number of slabs needed for test: 3
Non-Relaxing Fatigue Model
Under nonrelaxing loads, some elastomers exhibit enhanced fatigue life / slowed crack growth due to strain crystallization effects. The effect is measured using crack arrest experiments in which a crack growing initially under fully relaxing loads is gradually operated under increasingly nonrelaxing loads. This information is required when constructing rubber’s Haigh diagram for a crystallizing material.
Recommended for cases where cyclic minimum loading is greater than zero and material may strain crystallize.
Test is run under a range of nonrelaxing (R > 0) conditions.
Note: It is required to run FPM-C in order to run this Module
Experiment Overview
- fatigue crack growth arrest procedure with minimum strain sweep
- number of slabs needed for test: 1
Ozone Effect Module
Ozone is a trace gas that strongly reacts with some rubbers to produce surface cracking following exposure. Ozone cracking can limit useful product life, even when mechanical cycles operate below the mechanical fatigue threshold. The Endurica ozone attack testing method determines: ℇz the critical strain for ozone attack; Tz the critical tearing energy for ozone attack; and rz the rate of crack growth due to ozone attack.
Required when rubber that has a susceptibility to ozone attack is operating in an environment with ozone.
Experiment Overview
- images of crack development on specimen
- 3 replicates
- number of slabs needed for test: 1