Block loading sequence effects on fatigue in the copper alloy Cu-35%Ni-3.5%Cr

1994 ◽  
Vol 16 (2) ◽  
pp. 147-150 ◽  
Author(s):  
H Bomas
Keyword(s):  
Copper Alloy ◽  
Block Loading ◽  
Sequence Effects ◽  
Loading Sequence

Loading sequence effects on dragload and downdrag for pile foundation

2010 ◽  
Vol 16 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Gangqiang Kong ◽  
Qing Yang ◽  
Maotian Luan
Keyword(s):  
Pile Foundation ◽  
Sequence Effects ◽  
Loading Sequence

scholarly journals Investigation of fatigue crack growth under loading sequence effects using in-situ SEM testing

2018 ◽  
Vol 165 ◽  
pp. 22012
Author(s):  
Shan Jiang ◽  
Wei Zhang ◽  
Liang Cai ◽  
Zili Wang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Damage Zone ◽  
Shear Bands ◽  
Micro Cracks ◽  
Sequence Effects ◽  
Crack Propagation Process ◽  
Loading Sequence

Fatigue damage is one of the most important failure mechanisms in engineering components. The excited structures are usually subjected to spike loads in the fatigue weakness area during their service lives. The nonlinear loading sequence effects due to overloads are significant in the crack propagation process. In this paper, an in-situ scanning electron microscope (SEM) testing is performed to analyse the mechanisms of nonlinear fatigue crack growth affected by the load sequence. The crack tip behaviours under constant amplitude loading cycles superimposed by tensile overload were observed. The SEM experiment results reveal that the overload effects include the transient weakened area (shear bands and micro-cracks) and the relatively long-term retardation. Additionally, the observation loading sequence influence region is larger than the theoretical value. According to these SEM testing analyses, the Willenborg is modified considering the nonlinear loading sequence effects. In this approach, the damage zone concept is introduced to account for the instantaneous acceleration. Moreover, the loading sequence effect area is defined as the whole plastic zone due to overload rather than part of it. The proposed algorithm is validated by experiment data of 350WT steel and Al 2024-T351 specimens under constant loading with overloads. Good agreements are observed.

scholarly journals Fatigue Life Prediction of Composite Under Two Block Loading

2014 ◽  
Vol 4 (1) ◽  
pp. 587-590
Author(s):  
M. Bendouba ◽  
A. Aid ◽  
M. Benguediab
Keyword(s):  
Fatigue Life ◽  
Composite Materials ◽  
Composite Structures ◽  
Life Prediction ◽  
Fatigue Behaviour ◽  
Cycle Fatigue ◽  
Sequence Effect ◽  
Block Loading ◽  
Damage Indicator ◽  
Loading Sequence

The damage evolution mechanism is one of the important focuses of fatigue behaviour investigation of composite materials and also the foundation to predict fatigue life of composite structures for engineering applications. This paper is dedicated to damage investigation of composite materials under two block loading cycle fatigue conditions. The loading sequence effect and the influence of the cycle ratio of the first stage on the cumulative fatigue life are studied. Two loading sequences, i.e., high-to-low and low-to-high cases are considered. The proposed damage indicator is connected cycle by cycle to the S-N curve and the experimental results are in agreement with model expectations. Previous experimental research is employed for validation.

scholarly journals Fatigue Design of Steel Bridge Deck Asphalt Pavement Based on Nonlinear Damage Accumulation Theory

2021 ◽  
Vol 11 (12) ◽  
pp. 5668
Author(s):  
Xunqian Xu ◽  
Yu Li ◽  
Wei Huang ◽  
Dakai Chen ◽  
Chen Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Bridge Deck ◽  
Asphalt Pavement ◽  
Prediction Method ◽  
Fatigue Life Prediction ◽  
Steel Bridge ◽  
Fatigue Design ◽  
Sequence Effects ◽  
Loading Sequence

Based on the nonlinear damage theory, this paper aims to explore the fatigue performance of steel bridge deck asphalt pavement under multistage fatigue load. Manson–Halford cumulative damage model and the modified model were introduced to describe loading sequence effects, and interactions between multiple loads were represented in stress ratio. The fatigue life prediction method of steel bridge deck asphalt pavement was put forward, considering loading sequence effects and load interactions. The fatigue design of steel bridge deck asphalt pavement was investigated with the fatigue life prediction model. The effects of different load levels and loading sequence on the fatigue design parameters stress ratio of steel bridge deck asphalt pavement were studied. The design results were compared with experimental results, and the prediction results were based on traditional Miner’s theory. The analysis results showed that the fatigue life prediction method based on the nonlinear cumulative damage theory can effectively design and analyze the fatigue characteristics of asphalt pavement of steel bridge deck with high accuracy and reliability. The fatigue life prediction model of steel bridge deck asphalt pavement can well reflect loading sequence effects and load interactions. In addition, the design model has relatively few parameters; therefore, it can be applied to practical engineering design.

Loading sequence effects in two-level program-tests

1975 ◽  
Vol 17 (9) ◽  
pp. 307-312
Author(s):  
Alfred Buch
Keyword(s):  
Sequence Effects ◽  
Loading Sequence

scholarly journals A Review of the Loading Sequence Effects on the Fatigue Life Behaviour of Metallic Materials

2016 ◽  
Vol 9 (5) ◽  
pp. 189-200 ◽  
Author(s):  
K. A. Zakaria ◽  
◽  
S. Abdullah ◽  
M. J. Ghazali ◽  
◽  
...  
Keyword(s):  
Fatigue Life ◽  
Metallic Materials ◽  
Sequence Effects ◽  
Loading Sequence

Fatigue Life Prediction of Composite Laminates under Block Loading

2014 ◽  
Vol 697 ◽  
pp. 114-117
Author(s):  
Qing Hui Ji ◽  
Ping Zhu ◽  
Jia Hai Lu ◽  
Chao Zhu
Keyword(s):  
Fatigue Life ◽  
Composite Materials ◽  
Fatigue Damage ◽  
Life Prediction ◽  
Testing Machine ◽  
Damage Index ◽  
Block Loading ◽  
Proposed Model ◽  
Loading Sequence ◽  
Stress Ratios

The loading sequence effect and life prediction of carbon fiber-reinforced polymer (CFRP) composite materials were experimentally investigated in this paper. All fatigue tests of block loading under four stress ratios R (including 0.1, 0.5, 10 and –1) were carried out on the servo-hydraulic Shimadzu testing machine. The fatigue damage index derived from the linear Palmgren–Miner rule was as reference to evaluate the damage degree. The life prediction model based on residual strength theory was proposed. The experimental results showed that the effect of loading sequence on the fatigue damage was obvious. The relation between the parameter of the proposed model and the stress ratio was studied depending to different failure mode. At last, the contrast of prediction and experimental data indicated that the proposed model had enough accuracy to predict fatigue life of block loading for composite materials.

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