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1.
通过CS夹芯板抗弯性能的试验,重点研究织物加强对改善夹芯板抗弯及抗裂性能的作用。试验研究表明,织物加强的CS夹芯板具有很好的抗弯抗裂性能。并根据受弯机理分析,提出相应的开裂弯矩和极限弯矩计算公式,计算结果与试验结果吻合较好。 相似文献
2.
针对复合板结构中弯曲板波谐振频率计算相对复杂的问题,建立并分析了基于弯曲板波延迟线振荡器的理论模型,计算得到A0(0阶反对称)模式板波的谐振频率为41 MHz;为了验证理论分析的结果,利用有限元软件ANSYS建立了基于弯曲板波的延迟线振荡器的3D有限元模型,并对其进行了谐响应分析以及瞬态动力学分析。谐响应分析得到A0模式的谐振频率为37.2 MHz,与理论计算结果的相对误差为9.3%;瞬态动力学分析得到A0模式的谐振频率为39.1 MHz,与理论计算结果的相对误差为4.6%。计算和仿真为基于弯曲板波的延迟线振荡器的结构设计提供了重要的依据。 相似文献
3.
在铂催化剂的作用下,利用4-(β-羟基-γ-烯丙氧)丙氧基-2-羟基二苯甲酮MUV-O与含氢硅油PHMS在甲苯溶剂中的硅氢加成反应,合成了一种侧链携带有二苯甲酮类紫外吸收基团的聚硅氧烷PUVSi。对产物物化性能及其在织物整理中的应用性能进行了研究。结果表明,PUVSi的相对密度和折射率随着紫外吸收基团含量的增加而增大;相对分子质量分布变宽。用PUVSi整理所得织物柔软度提高,且随着PUVSi中紫外吸收基含量从0.045%增大至0.14%,弯曲刚度经纬总和从830mN增加至880mN;工作浴液的固含量从0.3%增至1.2%,织物的紫外光透过率从81%降至60%,而织物的弯曲刚度经纬总和则从266mN下降到234mN;将N-β-氨乙基-γ-氨丙基聚二甲基硅氧烷ASO-1和加入含氢量0·14%的PHMS所制成的PUVSi(PUVSi-1)复配,其整理织物柔软性强于单独使用PUVSi-1。乳化PUVSi时乳化剂T-55的用量(对PUVSi的质量分数)30%较为适宜。 相似文献
4.
5.
从混凝土受弯构件的基本假定和基本公式出发,推导出采用内力臂系数进行受弯承载力计算的简化公式。经过大量计算,分析了弯矩、配筋率和混凝土强度对内力臂系数的影响。最后,基于在我国混凝土梁纵向受拉钢筋配筋率基本不大于1.6%的情况,建议采用简化公式进行梁配筋设计时。内力臂系数可取0.80(C30混凝土,HRB 40钢筋)或0.85(C35混凝土,HRB 400钢筋)。 相似文献
6.
《International Journal of Pavement Engineering》2012,13(3):223-230
With the increased awareness of building sustainable transportation systems, recycled materials and industrial byproducts increasingly are being used in highway construction, especially as base materials. When compared to traditional base materials, such as crushed aggregate, recycled materials and industrial byproducts often display unique properties. However, the physical properties of recycled materials and industrial byproducts have yet to be fully characterised for the purpose of pavement design. This study evaluated the mechanical properties of a full-depth reclaimed pavement material (RPM) and RPM stabilised with high carbon/high calcium fly ash, and compared these with properties of a conventional crushed aggregate. It was found that RPM exhibited higher modulus than the traditional base course material (crushed aggregates) did. However, RPM also showed higher plastic strain than crushed aggregate, indicating a higher potential for rutting in RPM base. Adding high carbon/high calcium fly ash significantly increased the California Bearing Ratio (CBR) and resilient modulus and lowered plastic strain of RPM. The strength and stiffness of field-mixed RPM stabilised with fly ash was significantly lower than that of laboratory-mixed mixtures, as indicated by different measures, i.e., CBR, resilient modulus and unconfined compressive strength (UCS). Data obtained in this study, along with other data obtained from similar studies, indicate that there are good correlations between resilient modulus and CBR (R 2 = 0.96), as well as between resilient modulus and UCS (R 2 = 0.94) for recycled base materials stabilised with fly ash. However, there is still a need for more testing to further verify the proposed relationships. Nonetheless, the proposed relationships constitute the first such relationship proposed and can be useful in pavement design. Additionally, it is shown that flexural strength is about 20% of UCS as it is recommended for materials stabilised with other cementitious materials. 相似文献
7.
《International Journal of Pavement Engineering》2012,13(8):746-751
The work reported in this paper is based on a laboratory study carried out to investigate the feasibility of using copper slag, a by-product of copper refineries, as a partial replacement of sand in the preparation of pavement quality concrete (PQC) and dry lean concrete (DLC) mixes. A control mix for PQC was prepared with 400 kg/m3 of ordinary Portland cement (OPC) and water–cement (w–c) ratio of 0.40. Other concrete mixtures were then prepared by substituting 20%, 40%, 60%, 80% and 100% copper slag in control mix. Workability and bleeding of green concrete, compressive strength, flexural strength at 7 and 28 days, drying shrinkage and abrasion resistance were measured for all the concrete mixtures. DLC mixtures were designed with 150 kg/m3 of OPC and different blends of stone dust with 20%, 40%, 60% and 80% copper slag as fine aggregate. DLC mixes were then prepared with different water contents with a view to find out the optimum water content for achieving maximum density, and corresponding compressive strength at 7 and 28 days for each blend of stone dust and copper slag. The laboratory test results showed that the compressive strength of PQC 7 and 28 days was not affected by inclusion of any content of copper slag as fine aggregate in the concrete mixture. Small gradual increase in flexural strength at 28 days was observed with an increase in copper slag content. Drying shrinkage of PQC decreased with the increase in slag and the decrease in stone dust content. Abrasion resistance of concrete mixes containing slag was observed to be less as compared with that of non-slag concrete. Compressive strength of DLC decreased with the increase in copper slag content beyond 40%. Keeping in view the strength and other important requirement of PQC such as cohesiveness, segregation, finishing, texturing, shrinkage and abrasion resistance, it was concluded that a blend of stone dust with copper slag content up to 40% could be used as fine aggregate for PQC as well as DLC. 相似文献
8.
旋转轴系弯-扭振动耦合的数值分析 总被引：2，自引：0，他引：2
介绍了一种可以同时计算出旋转轴系的弯曲振动及扭转振动的瞬态响应的数值计算方法,该方法所依据的模型是一种分段的连续质量模型,具有比较好的计算精度,而与有限元方法比较,该方法的计算工作量及比较小。作者用该方法对旋转轴系弯曲振动与扭转振动的耦合问题进行了一些分析 相似文献
9.
Erol Sancaktar 《The Journal of Adhesion》1993,40(2):175-187
A mathematical analysis is performed to obtain relations for the radius of curvature and flexural moments for initially stretched bimaterial strips in which at least one of the materials exhibits viscoelastic behavior. One practical application of this analysis is for pressure sensitive tapes. Consequently, the radius of curvature and flexural moment relations are obtained as functions of backing and adhesive thicknesses and moduli for typical pressure sensitive tapes. The analysis shows that the flexural moment decreases as the backing thickness and/or backing modulus increase. Furthermore, the flexural moment decreases as the adhesive thickness and/or adhesive modulus decreases. 相似文献
10.
Abstract: This work aims in studying the mechanical behaviour of concrete, reinforced with steel fibres of different geometry and volume fraction. Experiments include compression tests and four‐point bending tests. Slump and air content tests were performed on fresh concrete. The flexural toughness, flexural strength and residual strength factors of the beam specimens were evaluated in accordance with ASTM C1609/C1609M‐05 standard. Improvement in the mechanical properties, in particular the toughness, was observed with the increase of the volume fraction of steel‐fibres in the concrete. The fibre geometry was found to be a key factor affecting the mechanical performance of the material. 相似文献