How does heat affect tensile strength

The following summarizes the general effects of temperature changes on mechanical properties of die casting alloys:. Creep does not occur below the threshold temperature.

The rate increases progressively with increasing temperature. Advertise With Us Contact. Geotech Investig Surv — Download references. You can also search for this author in PubMed Google Scholar. Dongming Zhang had the original idea for this study, all co-authors were involved in data analytics work, as well as writing and revising all parts of this manuscript. Correspondence to Zhang Dongming.

Reprints and Permissions. Dongming, Z. Geotech Geol Eng 36, — Download citation. Received : 14 December Accepted : 13 April Published : 23 April Issue Date : December Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content. Search SpringerLink Search. References ASTM Standard test method for splitting tensile strength of intact rock core specimens.

View author publications. In the process of splitting tensile strength testing, machine 2 applied loads at the speed of 0. The splitting tensile strength of concrete can be obtained by where is splitting tensile strength of the th concrete specimen, is the corresponding failure load under splitting, and is splitting area of specimens. Final splitting tensile strength can be calculated according to the same rules of getting.

In the process of prism compressive strength testing, machine 1 imposes loads at the speed of 0. The prism compressive strength of each specimen can be calculated by where is prism compressive strength of the th concrete specimen, is the corresponding failure load under compression, is bearing area of specimens, and in this paper.

Final prism compressive strength can be calculated according to the same rules of getting. The concrete slabs are also wrapped by preservative film to maintain humidity stability to eliminate the influence of moisture.

Firstly, the slabs are measured under intact condition and temperature effect on frequency for undamaged slab is discussed. Secondly, the midspan sections of slabs are cut by special machine to simulate damage. Damage severity is represented by cutting depth; it can be calculated by where is damage severity and and are widths of damaged and intact midspan sections, respectively.

The testing arrangements of cube compressive and splitting tensile strength are shown in Figures 4 and 5 , respectively. The testing results of concrete under different temperatures are listed in Table 2. The relationship between cube compressive strength, splitting tensile strength, and temperatures is shown in Figures 6 and 7.

Linear formulas are applied to simulate the relationship between cube compressive strength, splitting tensile strength, and temperature. They are listed in the following equations, respectively:. As can be seen from Figures 6 and 7 and Table 2 , the cube compressive strength and splitting tensile strength both decrease with the increasing of temperature. The cube compressive strength improves by The results are listed in Table 3 and Figure 8. The relationship between prism compressive strength and temperature is listed in.

The relationship reveals that prism compressive strength decreases with the increasing of temperature and presents linear character. The prism strength decreases by The testing arrangements of modulus of elasticity are shown in Figure 9. The measurement results and temperature effects on modulus of elasticity are listed in Table 4 and Figure Regression analysis is conducted through linear formula to represent the relationship between modulus of elasticity and temperature; it is listed in.

From Table 4 and Figure 10 , modulus of elasticity increases with the decreasing of temperature, and a good linear relationship is presented. The modulus of elasticity improves by The test process is illustrated in Figure Testing results of first order natural frequency for three slabs , , and are listed in Table 5. Temperature effect on frequency of slabs is also demonstrated in Figure It can be concluded that the influence of temperature on first order frequency is obvious.

The frequency decreases with the increasing of temperature, and it shows clear negative correlation. The results of slab are used as examples to investigate the variation of frequency under the integrated effect of temperature and damage. As can be seen from Table 6 and Figure 13 , the first order natural frequency decreases with the increasing of damage severity under the same temperature, while it decreases with the increasing of temperature under the same damage severity.

In damage identification of structures, change rate of natural frequency is an effective damage indicator. According to dynamic theory, damage of structure will lead to the reduction of frequencies. The corresponding change rates of first order frequency are calculated by 10 , and the results are listed in Table 7 and Figure In theory, damage of structure will lead to the reduction of frequency.

Therefore, the change rate of frequency is a negative value. It reveals that frequency changes caused by damage have been submerged by temperature effect, and damage identification results will be unreliable in practice. The range analysis is also conducted and listed in Table 7. As can be seen from this table, the maximum range caused by damage is The temperature effect is not negligible.

For a simply supported uniform beam with length , height , density , and modulus of elasticity , the undamped flexural vibration frequency of order can be calculated by [ 22 — 24 ]. Temperature effect on modulus of elasticity has been tested and listed in Table 8. Theoretical calculation results of the first order frequency can be obtained based on 11 ; they are shown in Table 8 and Figure As can be seen from Table 8 and Figure 15 , the calculated frequencies based on measured modulus of elasticity and dynamic theory are consistent with the measured ones.

The results indicate that temperature effect on frequency is mainly caused by the influence of temperature on modulus of elasticity. It can provide reference for damage identification of structures. Temperature effects on cube compressive strength, splitting tensile strength, prism compressive strength, modulus of elasticity, and frequency are conducted and the following conclusions can be drawn.

These static mechanical properties all decrease with the increasing of temperature, and linear formulas can effectively simulate their relationships. The compressive strength improves by Under the coupling effect of damage and temperature, the frequency change caused by damage would be submerged by temperature effect.

Therefore, it is necessary to consider the influence of temperature in damage identification of structure. The range analysis reveals that the temperature effect cannot be neglected in practice. Mechanism analysis of temperature effect on frequency is also conducted. The results demonstrated that it is mainly caused by the influence of temperature on modulus of elasticity.

The authors declare that there is no conflict of interests regarding the publication of this paper. The authors express their appreciation for the financial support of the National Natural Science Foundation of China under Grant nos.

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